Finding user equipment relaying path

Abstract

A method performed by a first network node is provided for finding a relay communication path to use when communicating with a second network node. The method comprises obtaining information related to at least one relay communication path between the first network node and the second network node. The information related to said at least one relay communication path is determined based on a simulation of operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. The method further comprises, based on the information related to said at least one relay communication path, determining the relay communication path to use for communicating with the second network node.

Description

FINDING USER EQUIPMENT RELAYING PATHTECHNICAL FIELD

[0001] This disclosure relates to finding user equipment (UE) relaying path.BACKGROUND

[0002] UE Relaying

[0003] New applications like extended reality (XR) require improved radio network (RN) performance in terms of, for example, increased user throughput and lower latency. To satisfy these demands, radio technology is being developed in the direction of, among others, wider transmission bandwidths, support of a higher number of transmit and receive antennas, and reduced transmission time intervals. To efficiently utilize the wider bandwidth, the link between a signal transmitter and a signal receiver must be relatively strong, especially in uplink, since UE transmission power is limited.

[0004] Network densification — i.e., deploying base station (BS) sites and sectors in a denser grid — is one way of improving the link as this reduces the distance between a UE and a BS. Network densification can, however, be both difficult and costly.

[0005] An alternative method under discussion is to use UE relaying to divide a singlehop link between a UE and a BS into a multi-hop path. Note that, in this disclosure, a link is defined as a direct connection between two network nodes (e.g., between a UE and a BS) while a path is defined as a sequence of links that connects two network nodes.

[0006] With UE relaying, the existing UE population is utilized for relaying messages. In the UE relaying, it may be possible to find a more favorable path between a UE and a BS, e g., since more power becomes available and since a multi-hop path may be associated with better propagation conditions as compared to a direct link between the UE and the BS.

[0007] FIG. 9 shows an example of UE relaying. In FIG. 9, a high attenuation non-Line- of-Sight (NLOS) link 922 is provided between a source UE 902 and a BS 904. The high attenuation NLOS link 922 constitutes a single hop direct link. Data may be exchanged between the source UE 902 and the BS 904 via the NLOS link 922. However, due to the existence ofbuildings in a direct communication path between the UE 902 and the BS 904, a high attenuation of signals may occur over the NLOS link 922.

[0008] Thus, instead of using the high attenuation NLOS link 922, two low attenuation Line-of-Sight (LOS) links 924 and 926 collectively constituting a two-hop path can be used to exchange databetween the UE 902 and the BS 904. More specifically, the UE 902 may transmit, to a UE 906, data that is to be delivered to the BS 904. Upon receiving the data from the UE 902, the UE 906 may forward the received data to the BS 904. Similarly, the BS 904 may transmit, to the UE 906, data that is to be delivered to the UE 902. Upon receiving the data from the BS 904, the UE 906 may forward the received data to the UE 902. Here, the UE 906 serves as a relay node.

[0009] In this disclosure, “relay node” is defined as an intermediate node in a signal path between a data sender (e.g., the UE 902) and a data receiver (e g., the BS 904), which is configured to forward data originated from the data sender towards the data receiver. To send and / or receive data over the UE-to-UE links it may be possible to use the side-link concept.

[0010] Path Finding and Path Maintenance

[0011] Like in any wireless multi-hop network or mesh network, path finding (a.k.a., “path selection” or “routing”) process is a central component of a UE relaying network. Path finding is the process of finding a proper path from a source node to one or several destination nodes in a network over which messages are transmitted from / to the source node to / from the destination node(s). Path maintenance refers to maintenance of an already existing communication path. One example of path maintenance is updating a path due to changes to the network topology.

[0012] In wireless networks, path finding procedures are often categorized as pro-active (table-driven) or re-active, on-demand procedures. In the pro-active (table-driven) path finding procedure, all nodes maintain path information for all other nodes in the network such that a path between any pair of nodes is always available. To build and distribute such routing tables, all nodes must regularly probe the local radio environment to estimate the radio channel towards its neighbors, and the information from the probing must be distributed to all other nodes in the network or gathered in a central node that calculates and distributes the routing tables.

[0013] On the contrary, in the on-demand path finding procedures, paths are created onlywhen needed, by initiating a path discovery procedure. In the path discovery procedure, the source node finds a path to the destination node(s) by flooding the network with path request probing packets. Once available, a path must also be maintained during its lifetime, accounting for changes to the network topology.

[0014] An advantage with the pro-active path finding is that a path is instantly available when needed. The downside is, however, that resources are spent on creating and maintaining paths that may never be used. The pro-active path finding is typically preferred for small networks.

[0015] As compared to the pro-active path finding, in the on-demand path finding, resources are only spent on paths that are being utilized. The downside is, however, that it takes some time until the path becomes available. For the both pro-active and the on-demand path finding, communication resources must be set aside to create and maintain paths between nodes in the network.SUMMARY

[0016] Certain challenges presently exist in UE relaying. One of the challenges is creating and maintaining good paths between source nodes and destination nodes quickly (i.e., with low delay) at low cost. This is because all existing path finding procedures spend a considerable amount of radio resources for creating and maintaining network paths.

[0017] For example, in the pro-active path finding procedures, radio resources are used to create and maintain paths between all candidate source and destination nodes. Even though this path creation and maintenance between all candidate nodes allows paths to become available instantly when needed, this instant availability of the paths is obtained at the cost of a high radio resource utilization. As compared to the pro-active path finding procedures, in the reactive path finding procedures, less resources are spent on path creation and maintenance. However, the reactive path finding procedures may still require substantial usage of network resources.

[0018] More specifically, in both the pro-active and re-active path finding procedures, the quality of node-to-node links (e.g., UE-UE links) is typically estimated by probing the radio channel between the respective nodes. This probing, however, generally consumes radio resources, creates interference, and drains the energy (e.g., batteries) of the involved nodes. Furthermore, during this probing, the nodes may be blocked from performing other functions.

[0019] Therefore, there is a need for a path finding / maintaining procedure that does not require substantial energy consumption of candidate nodes and that does not create any substantial interference on the operations of the candidate nodes.

[0020] Accordingly, in one aspect of some embodiments of this disclosure, there is provided a method performed by a first network node to find a relay communication path to use when communicating with a second network node. The method comprises obtaining information related to at least one relay communication path between the first network node and the second network node, wherein the information related to said at least one relay communication path is determined based on a simulation of operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. The method further comprises, based on the information related to said at least one relay communication path, determining the relay communication path to use for communicating with the second network node.

[0021] In another aspect, there is provided a method performed by a model node for establishing a relay communication path between a first network node and a second network node. The method comprises simulating operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. The method further comprises, based on a result of the simulation, determining information related to at least one relay communication path between the first network node and the second network node; and transmitting, to the first network node, the information related to said at least one relay communication path between the first network node and the second network node.

[0022] In a different aspect, there is provided a computer program comprising instructions which when executed by processing circuitry cause the processing circuitry to perform the method of any one of the above embodiments.

[0023] In a different aspect, there is provided a carrier containing the computer program of the above embodiment, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer readable storage medium.

[0024] In a different aspect, there is provided a first network node for finding a relaycommunication path to use when communicating with a second network node. The first network node is configured to obtain information related to at least one relay communication path between the first network node and the second network node, wherein the information related to said at least one relay communication path is determined based on a simulation of operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. The first network node is further configured to, based on the information related to said at least one relay communication path, determine the relay communication path to use for communicating with the second network node.

[0025] In a different aspect, there is provided a model node for establishing a relay communication path between a first network node and a second network node. The model node is configured to simulate operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. The model node is further configured to, based on a result of the simulation, determine information related to at least one relay communication path between the first network node and the second network node; and transmit, to the first network node, the information related to said at least one relay communication path between the first network node and the second network node.

[0026] In a different aspect, there is provided an apparatus comprising: a processing circuitry; and a memory, said memory containing instructions executable by said processing circuitry, whereby the apparatus is operative to perform the method of any one of the above embodiments.

[0027] Some embodiments of this disclosure provide one or more of the following advantages:

[0028] First, the resources of a radio network used for path fmding / maintenance can be significantly reduced or even eliminated. This releases the network resources for other data communication usage and reduces interference in the radio network, thereby increasing the network efficiency.

[0029] Second, the impact of path finding / maintenance on candidate nodes (e.g., candidate relay UEs) can be reduced or eliminated because, for example, no energy and processing poweris consumed by the candidate nodes for the path finding / maintenance, and the operations of the candidate nodes will not be blocked by the path finding / maintenance.

[0030] Third, like the pro-active path finding procedures, the path finding procedure according to some embodiments of this disclosure allows a path to be instantly available when needed. Also the path maintenance procedure according to some embodiments allow quickly accommodating any changes to the network topology.BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments.

[0032] FIG. 1 shows an exemplary network environment.

[0033] FIG. 2 shows a process according to some embodiments.

[0034] FIG. 3 shows a simplified example of a digital twin.

[0035] FIG. 4 shows a process according to some embodiments.

[0036] FIG. 5 shows a process according to some embodiments.

[0037] FIG. 6 shows a process according to some embodiments.

[0038] FIG. 7 shows an apparatus according to some embodiments.

[0039] FIG. 8 shows an apparatus according to some embodiments.

[0040] FIG. 9 shows possible communication paths between a UE and a BS.DETAILED DESCRIPTION

[0041] FIG. 1 shows a simplified real-world environment 100 where some embodiments of this disclosure can be applied. As shown in FIG. 1, in the real-world environment 100, there are provided a first network node (e.g., a UE such as a mobile phone, a tablet, a computer, a vehicle, an internet-of-things (loT) device, etc.) 102, a first candidate relay network node (e g., an access point or a UE) 104, a second candidate relay network node (e.g., an access point or a UE) 106, a third candidate relay network node (e.g., an access point or a UE) 108, a second network node (e.g., a base station such as gNB) 112, a model node 114, and buildings 116. In this disclosure, a group of candidate relay network nodes (e.g., 104, 106, 108, etc.) may bereferred to as “a candidate group of relay network nodes.”

[0042] Even though each of the network nodes 102-114 is not limited to a specific device type, for simple explanation purpose only, in the rest of this disclosure, a UE will be used as an example of each of the network nodes 102-108 and gNB will be used as an example of the second network node 112. Thus, in the rest of this disclosure, the first network node 102 will be referred to as “UE 102,” each of the candidate relay network nodes 104 / 106 / 108 will be referred to as candidate relay UEs 104 / 106 / 108, and the second network node 112 will be referred to as “gNB 112.”

[0043] FIG. 1 shows that a direct data communication path (hereinafter just “path”) 156 between the UE 102 and the gNB 112 is not available or too weak due to, for example, the presence of the buildings 116. More specifically, because the buildings 116 block signals travelling between the UE 102 and the gNB 112, the path 156 cannot be used for data communication between the UE 102 and the gNB 112.

[0044] Therefore, to perform the data communication between the UE 102 and the gNB 112, relay paths may be used. FIG. 1 shows that there are two candidate relay paths 152 and 154 between the UE 102 and the gNB 112.

[0045] The candidate relay path 152 is formed by a link 126 between the UE 102 and the candidate relay UE 106, a link 128 between the candidate relay UE 106 and the candidate relay UE 108, and a link 130 between the candidate relay UE 108 and the gNB 112. The candidate relay path 154 is formed by a link 122 between the UE 102 and the candidate relay UE 104 and a link 124 between the candidate relay UE 104 and the gNB 112. Note that the number of the UEs, the locations of the UEs, the location of the gNB, the links between the UEs, and the paths between the UE 102 and the gNB 104 shown in FIG. 1 are provided for illustration purpose only, and do not limit the embodiments of this disclosure in any way.

[0046] In order to find and / or maintain the optimal path between the UE 102 and the gNB 112 (e g., in order to determine which one of the candidate relay paths 152 and 154 to use for the data communication between the UE 102 and the gNB 112), the qualities of links that can be established between two nodes (e.g., the UEs 102-108 and the BS 112) in the environment 100 (e g., the links 122-130) need to be determined. In the existing path finding / maintenance procedure, estimating such link qualities requires actual probing (i.e., transmitting reference signals and measuring the qualities of the received reference signals). Such actual probing,however, may consume radio resources, create interference in the network, drain the energy of the UEs, and / or prevent the UEs from performing other functions.

[0047] In order to solve the above problems, according to some embodiments, the model node 114 is provided. The model node 114 is configured to store a model. The model is configured to simulate the real -world environment 100, and the optimal path between the UE 102 and the gNB 112 may be found and / or maintained based on a result of the simulation.

[0048] One example of the model stored in the model node 114 is a radio network digital twin. As mentioned in Reference [1] listed below, a digital twin is a “virtual representation of real-world entities and processes, synchronized at a specified frequency and fidelity.” The radio network digital twin may contain information of the environment in which a radio network operates. The environment may be described by two-dimensional (2D) or three-dimensional (3D) maps using 2D / 3D representations of terrain, buildings, roads, and objects, and with attributes. The information of the environment may also include deployment information about sites, sectors, cells (e.g., site and sector positions, antenna installations, cell carrier frequencies and bandwidths, etc.), and user equipments (UEs - a.k.a., “devices”) each of which can be represented by, for example, a device type, its position, and its mobility category.

[0049] The radio network digital twin may include various models such as radio propagation models, physical layer models, medium access layer models, etc., which can be utilized to model the network behavior, e.g., via simulations.

[0050] Considering that the digital representations of the radio network digital twin describe various items that are different in nature, the representations of the items may be updated on different time scales. For example, the environment such as terrain and buildings, is essentially static or semi-static in nature, and thus it would typically be sufficient to update the representation of the environment less frequently (e.g., on a weekly or monthly basis).

[0051] On the contrary, the representation of the radio network may be updated more frequently (e.g., on a daily or hourly basis). Even though the network sites, sectors, and frequency bands typically do not change very often, network parameters may change more frequently, and thus it may be required that such frequent changes are reflected in the digital twin relatively fast.

[0052] FIG. 2 shows a process 200 for finding and maintaining the optimal path between the UE 102 and the gNB 112 using the model (e.g., a digital twin), according to someembodiments. Each step of the process 200 may be performed by the gNB 112 and / or the model node 114. The process 200 may begin with step s202.

[0053] The step s202 comprises the model node 114 initializing the model (e.g., a digital twin) stored in the model node 114. During the initialization, the model is created and synchronized to real-world objects in the environment 100. The representations of different real- world objects may be updated at different frequencies and with different levels of fidelity. The model may include a virtual representation of the real-world environment 100, which may be provided in the form of a two-dimensional (2D) or a three-dimensional (3D) map. FIG. 3 shows a simplified 3D map of an exemplary virtual representation of a real-world environment.

[0054] The model may include various attributes. Examples of the model attributes include, but are not limited to, positions of the UEs 102-108, the position of the gNB 112, the positions of buildings 116, configurations of each of the UEs 102-108, configuration of the gNB 112, etc. The configuration of each of the UE 102-108 and the gNB 112 may include a number of transmit (TX) beams to use for transmitting data, a number of receive (RX) beams to use for receiving data, types of available beams (e.g., a list of wide beams, a list of narrow beams, etc.), antenna positions, etc.

[0055] The model attributes may be updated differently. For example, in case the UEs 102-108 are mobile, their locations may change frequently. In such case, the model attributes corresponding to the positions of the UEs may be updated frequently. On the contrary, since the gNB 112 is stationary, the model attribute corresponding to the position of the gNB 112 may be updated infrequently or may not be updated at all. Table 1 below shows examples of the attributes of the model stored in the model node 114 for the real -world environment 100.Table 1

[0056] After initializing the model, the process 200 may proceed to step s204. The step s204 comprises the model node 114 performing virtual channel probing using the model. More specifically, in the step s204, the model stored in the model node 114 may determine estimated qualities of the links 122-130 based on the virtual representation of the real-world environment 100 and the model attributes. Here, the process of estimating the link qualities using the model is referred to as virtual channel probing. An estimated quality of a link may indicate an expected data transmission rate over the link.

[0057] There are various ways of performing the virtual channel probing. One exemplary way is using, in the virtual representation of the environment 100, ray-tracing channel modeling techniques to calculate pathloss between a pair of nodes (e.g., the UEs 102-108 and the gNB 112) at two known locations in a digital map. Using the knowledge about the capabilities of the UEs 102-108 and the gNB 112 (e.g., transmission power, a number of TX antennas, a number of RX antennas, etc.), the model may determine estimated qualities of the links 122-130.

[0058] The model may determine an estimated link quality for all pairs of nodes in the real -world environment or only for some pairs of nodes in the real -world environment. For example, in some embodiments, the model may only determine estimated link qualities for the links 122-130. However, in other embodiments, the model may determine the estimated link qualities not only for the links 122-130 but also for other links that can be established between two nodes in the environment 100 (e.g., the link between the UE 102 and the candidate relay UE 108, the link between the candidate relay UE 104 and the candidate relay UE 108, etc.). The determined link quality estimates may be stored in a matrix format in a database. Table 2 below show a simplified example of the link quality estimates determined and stored in the step s204.Table 2

[0059] Even though, in Table 2, expected (and / or achievable) data transmission rate over a link (“rate metric”) is provided as an example of a link quality of the link, the link quality may indicate any one of a time it takes for data packets to be transmitted over the link (“delay metric”), a current load of relay node(s) forming the link (“load metric”), and or an amount of energy consumption for transmitting data packets over the link (“energy consumption metric”).

[0060] In some embodiments, a link quality of a link may be associated based on a combination of one or more of the rate metric, the delay metric, the load metric, and the energy consumption metric.

[0061] After performing the virtual channel probing, the process 200 may proceed to step s206. The step s206 comprises the model node 114 estimating link costs (i.e., costs associated with links) using the model. More specifically, in the step s206, the model node 114 may determine a cost associated with each of the links 122-130 based on the link quality estimates obtained in the step s204. The cost associated with each of the links 122-130 may indicate the cost of transmitting and / or receiving data over the link.

[0062] In case an expected rate of transmitting data over a link is used to indicate the quality of the link, a link cost for the link may be defined based on the expected data transmission rate. The link cost may be inversely proportional to the link quality. More specifically, in one example, the link cost of a link may represent the time it takes to transmit one bit of information over the link. In this example, the link cost c£may be defined as1 Ci = — where rtis the expected data rate on the link z.

[0063] After estimating the link costs, the process 200 may proceed to step s208. The step s208 comprises the model node 114 finding the optimal (i.e., best) path between the UE 102 and the gNB 112 using the model.

[0064] There are many well-known path finding methods and protocols, and any of these can be used in the model to find a suitable path between the UE 102 and the gNB 112. For example, in some embodiments, using the estimated link costs as an input, an algorithm like the Bellman-Ford algorithm or Dijkstra’s algorithm may be used to find the path that is associatedwith the lowest total cost (e.g., where the total cost is the sum of all link costs in the path) and set the found path as the optimal path. The path with the lowest cost is often called the shortest path.

[0065] Referring back to FIG. 1 , as shown in the figure, there are two candidate relay paths 152 and 154 between the UE 102 and the gNB 112. In the step s206, the link costs for the links 122-130 are determined. Then, in the step s208, the cost for the candidate relay path 152 may be determined by combining the link costs of the links 126, 128, and 130. Similarly, the cost for the candidate relay path 154 may be determined by combining the link costs for the links 122 and 124. Then the cost for the candidate relay path 152 and the cost for the candidate relay path 154 may be compared to each other, and the candidate relay path having the lower cost may be selected as the optimal path between the UE 102 and the gNB 112. For simple explanation purpose, it will be assumed that the cost for the candidate relay path 152 is lower than the cost for the candidate relay path 154, and thus, in the step s208, the relay path 152 is selected as the optimal relay path between the UE 102 and the gNB 112.

[0066] After selecting the relay path 152 as the optimal relay path between the UE 102 and the gNB 112, the process 200 may proceed to step s210. The step s210 comprises performing path setup. More specifically, once the model node 114 selects the relay path 152 as the optimal relay path between the UE 102 and the gNB 112, the model node 114 may transmit information related to the relay path 152 to the gNB 112.

[0067] Upon receiving this information, the gNB 112 will know that the relay UEs 106 and 108 exist in the relay path 156. Then, in the step s210, the gNB 112 may signal the relay UEs 106 and 108 to configure their settings such that the relay UEs 106 and 108 can be used for a relay data communication between the UE 102 and the gNB 112. This signaling from the gNB 112 to each of the relay UEs 106 and 108 may be performed directly or via one or more intermediate nodes. For example, the gNB 112 may signal the relay UE 106 directly or via the relay UE 108.

[0068] After performing the path setup, the process 200 may proceed to step s212. The step s212 comprises performing data transmission between the UE 102 and the gNB 112. More specifically, after the relay path 152 is selected as the optimal path between the UE 102 and the gNB 112, the UE 102 and the gNB 112 can start exchanging data with each other via the relay path 152. The communications follow established protocols and procedures for UE-to-UE andUE-to-BS communication, e.g., such as scheduling and link adaptation.

[0069] After performing the data transmission between the UE 102 and the gNB 112 using the selected relay path, the process 200 may proceed to step s214. The step s214 comprises performing path maintenance based on virtual channel probing.

[0070] The model (e.g., a DT) stored in the model node 114 may be synchronized periodically to the real-world environment 100. For the path maintenance, at any time when one or more conditions in the real -world environment 100 change sufficiently, the steps s204-s208 may be performed again. Examples of such conditions include, but are not limited to, detecting an availability of a new candidate relay UE, detecting any substantial change in the location of any of the UEs 102-108, detecting appearance of any new object (e.g., a truck) between the UE 102 and the gNB 112, detecting disappearance of any object existed between the UE 102 and the gNB 112, etc.

[0071] More specifically, in case a condition in the real -world environment 100 has been changed and such change is detected in the model, the model node 114 may re-perform the virtual channel probing (in the step s204), re-determine the link costs (in the step s206), and refind an optimal relay path between the UE 102 and the gNB 112 (in the step s208). If the new optimal relay path is different from the old one, then the gNB 112 may re-perform the step s210 to perform the path setup for the new optimal relay path.

[0072] As explained above, in the process 200 shown in FIG. 2, the model node 114 performs the steps s202-s208. More specifically, in the process 200, the model node initializes the model (in the step s202), performs the virtual channel probing using the model, thereby obtaining the link quality estimates (in the step s204), estimates the link costs based on the link quality estimates (in the step s206), finds the optimal relay path between the UE 102 and the gNB 112 (in the step s208), and transmits, to the gNB 112, information indicating the found optimal relay path. However, in some embodiments, one or more of the steps s202-s208 may be performed by the gNB 112.

[0073] For example, in some embodiments, after the model node 114 performs the virtual channel probing, thereby obtaining the link quality estimates (in the step s204), the model node 114 may transmit, to the gNB 112, information indicating the link quality estimates Upon receiving this information, the gNB 112 may perform the steps s206 and s208 — i.e., estimating the link costs based on the link quality estimates (the step s206) and selecting an optimal relaypath based on the estimated link costs (the step s208).

[0074] In other embodiments, after the model node 114 performs the virtual channel probing, thereby obtaining the link quality estimates (in the step s204) and estimates the link costs based on the link quality estimates (in the step s206), the model node 114 may transmit, to the gNB 112, information related to the estimated link costs. Upon receiving this information, the gNB 112 may perform the step s208 — i.e., selecting an optimal relay path based on the estimated link costs.

[0075] FIG. 4 shows a message sequence chart 400 of an exemplary procedure for finding and setting up an optimal relay path between the UE 102 and the gNB 112 according to some embodiments. The procedure may begin with step s402.

[0076] The step s402 comprises the UE 102 transmitting, to the gNB 112, a request to initiate uplink transmission to the gNB 112. Upon receiving this request, the gNB 112 may initiate a path discovery process. In performing the path discovery process, the gNB 112 may transmit in the step s404 a path finding request message to the model node 114.

[0077] Upon receiving this path finding request message, the model node 114 may use the model (e.g., a digital twin) to perform the steps s202-s208 of the process 200 shown in FIG. 2 to find an optimal relay path between the UE 102 and the gNB 112. After finding the optimal relay path, in the step s406, the model node 114 may transmit, to the gNB 112, a path finding response message which indicates the found optimal relay path between the UE 102 and the gNB 112.

[0078] To set up the found optimal relay path in the radio network, in step s408, the gNB 112 may forward this information to the UE 102 as well as the relay UEs existing in the selected relay path. For example, in case the relay path 152 is selected by the model node 114, the gNB 112 may forward the information to the relay UEs 106 and 108 since the relay UEs 106 and 108 are in the relay path 152. In forwarding this information to each of the UEs 102, 106, and 108, the gNB 112 may forward this information to each of the UEs either directly or indirectly. For example, as shown in FIG. 4, the gNB 112 may forward this information to the UE 102 indirectly via the relay UEs 106 and 108. Similarly, the gNB 112 may forward this information to the relay UE 106 indirectly via the relay UE 108.

[0079] After receiving the information in the step s408, the UEs 102, 106, 108 and the gNB 112 may be configured to set up the relay path 152. Once the relay path 152 is set up, the UE 102 may initiate the data transmission in the step s410. In performing the data transmission,the UE 102 may transmit the data to the relay UE 106 which forwards the data to the relay UE 108 which forwards the data to the gNB 112.

[0080] FIG. 5 shows a process 500 performed by a first network node (e.g., the gNB 112) to find a relay communication path to use when communicating with a second network node (e.g., the UE 102), according to some embodiments. The process 500 may begin with step s502. The step s502 comprises obtaining information related to at least one relay communication path between the first network node and the second network node, wherein the information related to said at least one relay communication path is determined based on a simulation of operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. The step s504 comprises, based on the information related to said at least one relay communication path, determining the relay communication path to use for communicating with the second network node.

[0081] In some embodiments, the virtual representation of the network environment is a digital twin, DT, of the network environment.

[0082] In some embodiments, the process 500 comprises transmitting, to a model node, a request related to one or more relay communication paths between the first network node and the second network node; and after transmitting the request, receiving, from the model node, a response including the information related to said at least one relay communication path between the first network node and the second network node, wherein the request related to said one or more relay communication paths is transmitted from the first network node to the model node i) periodically or ii) based on that a condition is satisfied.

[0083] In some embodiments, the condition is the first network node receiving, from the second network node, a request to initiate uplink, UL, data transmission and / or downlink, DL, data transmission.

[0084] In some embodiments, the information related to said at least one relay communication path is determined based on an estimated link quality of a communication link between at least one pair of network nodes included in the first network node, the second network node, and the candidate group of network nodes, and the link quality of the communication link between said at least one pair of network nodes is estimated by the model node based on asimulation of operations of said at least one pair of network nodes in the virtual representation of the network environment.

[0085] In some embodiments, said at least one pair of network nodes includes a first pair of network nodes and a second pair of network nodes, the information related to said at least one relay communication path indicates a first estimated link quality of a first communication link between the first pair of network nodes and a second estimated link quality of a second communication link between the second pair of network nodes, and the relay communication path to use for communicating with the second network node is selected based on the first and second estimated link qualities.

[0086] In some embodiments, the process 500 comprises based on the first estimated link quality of the first communication link and the second estimated link quality of the second communication link, forming a first candidate relay communication path which includes the first communication link between the first pair of network nodes and a second candidate relay communication path which includes the second communication link between the second pair of network nodes, wherein determining the relay communication path to use for communicating with the second network node comprises selecting one of the first and second candidate relay communication paths.

[0087] In some embodiments, the first candidate relay communication path comprises a first group of one or more communication links including the first communication link, the second candidate relay communication path comprises a second group of one or more communication links including the second communication link. The process 500 comprises: determining a cost of transmitting and / or receiving data over each communication link included in the first group; summing up the costs of transmitting and / or receiving data over the communication links included in the first group; determining a cost of transmitting and / or receiving data over each communication link included in the second group; and summing up the costs of transmitting and / or receiving data over the communication links included in the second group, and one of the first and second candidate relay communication paths is selected based on a comparison of the sum of the costs for the first group and the sum of the costs for the second group.

[0088] In some embodiments, the information related to said at least one relay communication path indicates a list of candidate relay communication paths between the first and second network nodes and a cost of transmitting and / or receiving data over each candidate relaycommunication path included in the list, and determining the relay communication path to use for communicating with the second network node comprises selecting a relay communication path included in the list based on the costs.

[0089] In some embodiments, each candidate relay communication path included in the list is formed by the model node based on an estimated link quality of a communication link between each of a plurality of pairs of network nodes included in the first network node, the second network node, and the candidate group of relay network nodes, and the link quality of the communications link between each of the plurality of pairs of network nodes is estimated by the model node based on a simulation of operations of the plurality of pairs of network nodes in the virtual representation of the network environment.

[0090] In some embodiments, the information related to said at least one relay communication path indicates the relay communication path to use for communicating with the second network node.

[0091] In some embodiments, the relay communication path to use for communicating with the second network node is selected from a list of candidate relay communication paths formed by model node in the virtual representation of the network environment, and the list of candidate relay communication paths is formed by the model node based on estimated link qualities of communication links between each of a plurality of pairs of network nodes included in the first network node, the second network node, and the candidate group of relay network nodes.

[0092] FIG. 6 shows a process 600 performed by a model node (e.g., the model node 114) for establishing a relay communication path between a first network node (e.g., the gNB 112) and a second network node (e.g., the UE 102), according to some embodiments. The process 600 may begin with step s602. The step s602 comprises simulating operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located. Step s604 comprises, based on a result of the simulation, determining information related to at least one relay communication path between the first network node and the second network node. Step s606 comprises transmitting, to the first network node, the information related to said at least one relay communication path between the first network node and the second network node.

[0093] In some embodiments, the virtual representation of the network environment is adigital twin, DT, of the network environment.

[0094] In some embodiments, the simulating comprises simulating operations of at least one pair of network nodes included in the first network node, the second network node, and the candidate group of network nodes in the virtual representation of the network environment, and based on a result of the simulation of the operations of said at least one pair of network nodes, estimating a link quality of a communication link between said at least one pair of network nodes, wherein the information related to said at least one relay communication path is determined based on the estimated link quality of the communication link between said at least one pair of network nodes.

[0095] In some embodiments, said at least one pair of network nodes includes a first pair of network nodes and a second pair of network nodes, and estimating the link quality of the communication link between said at least one pair of network nodes comprises: estimating a first link quality of a first communication link between the first pair of network nodes; and estimating a second link quality of a second communication link between the second pair of network nodes.

[0096] In some embodiments, the information transmitted from the model node to the first network node indicates the estimated first link quality of the first communication link and the estimated second link quality of the second communication link.

[0097] In some embodiments, the process 500 comprises based on the first estimated link quality of the first communication link and the second estimated link quality of the second communication link, forming: a first candidate relay communication path which includes the first communication link between the first pair of network nodes; and a second candidate relay communication path which includes the second communication link between the second pair of network nodes.

[0098] In some embodiments, the process 500 comprises determining a first cost of transmitting and / or receiving data over the first candidate relay communication path; and determining a second cost of transmitting and / or receiving data over the second candidate relay communication path.

[0099] In some embodiments, the first candidate relay communication path comprises a first group of two or more communication links including the first communication link, the second candidate relay communication path comprises a second group of two or more communication links including the second communication link. The process 500 comprises: determining a cost oftransmitting and / or receiving data over each communication link included in the first group; summing up the costs of transmitting and / or receiving data over the communication links included in the first group, thereby determining the first cost; determining a cost of transmitting and / or receiving data over each communication link included in the second group; and summing up the costs of transmitting and / or receiving data over the communication links included in the second group, thereby determining the second cost.

[0100] In some embodiments, the information transmitted from the model node to the first network node indicates: the first candidate relay communication path; the second candidate relay communication path; the first cost; and the second cost.

[0101] In some embodiments, the process 600 comprises selecting one of the first and second candidate relay communication paths based on a comparison of the first cost and the second cost, wherein the information transmitted from the model node to the first network node indicates the selected candidate relay communication path.

[0102] FIG. 7 is a block diagram of the second network node 112, according to some embodiments for performing the method shown in FIG. 5. As shown in FIG. 7, the second network node 112 may comprise: processing circuitry (PC) 702, which comprises one or more processors (P) 755 (e.g., a general purpose microprocessor and / or one or more other processors, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGAs), and the like), which processors may be co-located in a single housing or in a single data center or may be geographically distributed (i.e., base station may be a distributed computing apparatus or a monolithic computing apparatus); a network interface 768 comprising a transmitter (Tx) 765 and a receiver (Rx) 767 for enabling the second network node 112 to transmit data to and receive data from other nodes connected to a network 110 (e.g., an Internet Protocol (IP) network) to which network interface 768 is connected; communication circuitry 748 (e.g., radio transceiver circuitry comprising an Rx 747 and a Tx 745) coupled to an antenna system 749 for wireless communication with UEs or other nodes; and a storage unit (a.k.a., “data storage system”) 708, which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In embodiments where PC 702 includes a programmable processor, a computer readable storage medium (CRSM) 742 may be provided. CRSM 742 may store a computer program (CP) 743 comprising computer readable instructions (CRI) 744. CRSM 742 may be a non-transitory computer readable medium, such as, magnetic media (e.g., a hard disk), optical media, memorydevices (e.g., random access memory, flash memory), and the like. In some embodiments, the CRI 744 of computer program 743 is configured such that when executed by PC 702, the CRI causes the second network node 112 to perform steps described herein (e g., steps described herein with reference to one or more flow charts). In other embodiments, the second network node 112 may be configured to perform steps described herein without the need for code. That is, for example, PC 702 may consist merely of one or more ASICs. Hence, the features of the embodiments described herein may be implemented in hardware and / or software.

[0103] FIG. 8 is a block diagram of network node 800 (e.g., the model node 114), according to some embodiments. As shown in FIG. 8, network node 800 may comprise: processing circuitry (PC) 802, which comprises one or more processors (P) 855 (e.g., one or more general purpose microprocessors and / or one or more other processors, such as an application specific integrated circuit (ASIC), field-programmable gate arrays (FPGAs), and the like), which processors may be co-located in a single housing or in a single data center or may be geographically distributed (e.g., network node 800 may be a distributed computing apparatus comprising two or more computers or a monolithic computing apparatus consisting of a single computer); at least one network interface 848 (e g., a physical interface or air interface) comprising a transmitter (Tx) 845 and a receiver (Rx) 847 for enabling network node 800 to transmit data to and receive data from other nodes connected to network 110 (e.g., an Internet Protocol (IP) network) to which network interface 848 is connected (physically or wirelessly) (e.g., network interface 848 may be coupled to an antenna arrangement comprising one or more antennas for enabling network node 800 to wirelessly transmit / receive data); and a storage unit (a.k.a., “data storage system”) 808, which may include one or more non-volatile storage devices and / or one or more volatile storage devices. In embodiments where PC 802 includes a programmable processor, a computer readable storage medium (CRSM) 842 may be provided. CRSM 842 may store a computer program (CP) 843 comprising computer readable instructions (CRI) 844. CRSM 842 may be a non-transitory computer readable medium, such as, magnetic media (e.g., a hard disk), optical media, memory devices (e.g., random access memory, flash memory), and the like. In some embodiments, the CRI 844 of computer program 843 is configured such that when executed by PC 802, the CRI causes network node 800 to perform steps described herein (e.g., steps described herein with reference to the flow charts). In other embodiments, network node 800 may be configured to perform steps described herein withoutthe need for code. That is, for example, PC 802 may consist merely of one or more ASICs. Hence, the features of the embodiments described herein may be implemented in hardware and / or software.

[0104] While various embodiments are described herein, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of this disclosure should not be limited by any of the above-described exemplary embodiments. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the disclosure unless otherwise indicated herein or otherwise clearly contradicted by context.

[0105] As used herein transmitting a message “to” or “toward” an intended recipient encompasses transmitting the message directly to the intended recipient or transmitting the message indirectly to the intended recipient (i.e., one or more other nodes are used to relay the message from the source node to the intended recipient). Likewise, as used herein receiving a message “from” a sender encompasses receiving the message directly from the sender or indirectly from the sender (i.e., one or more nodes are used to relay the message from the sender to the receiving node). Further, as used herein “a” means “at least one” or “one or more.”

[0106] Additionally, while the processes described above and illustrated in the drawings are shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and some steps may be performed in parallel.

[0107] References

Claims

CLAIMS1. A method (500) performed by a first network node (112) to find a relay communication path to use when communicating with a second network node (102), the method comprising: obtaining (s502) information related to at least one relay communication path between the first network node and the second network node, wherein the information related to said at least one relay communication path is determined based on a simulation of operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located; and based on the information related to said at least one relay communication path, determining (s504) the relay communication path to use for communicating with the second network node.

2. The method of claim 1, wherein the virtual representation of the network environment is a digital twin, DT, of the network environment.

3. The method of claim 1 or 2, the method comprising: transmitting, to a model node, a request related to one or more relay communication paths between the first network node and the second network node; and after transmitting the request, receiving, from the model node, a response including the information related to said at least one relay communication path between the first network node and the second network node, wherein the request related to said one or more relay communication paths is transmitted from the first network node to the model node i) periodically or ii) based on that a condition is satisfied.

4. The method of claim 3, wherein the condition is the first network node receiving, from the second network node, a request to initiate uplink, UL, data transmission and / or downlink, DL, data transmission.

5. The method of any one of claims 3-4, wherein the information related to said at least one relay communication path is determined based on an estimated link quality of a communication link between at least one pair of network nodes included in the first network node, the second network node, and the candidate group of network nodes, and the link quality of the communication link between said at least one pair of network nodes is estimated by the model node based on a simulation of operations of said at least one pair of network nodes in the virtual representation of the network environment.

6. The method of claim 5, wherein said at least one pair of network nodes includes a first pair of network nodes and a second pair of network nodes, the information related to said at least one relay communication path indicates a first estimated link quality of a first communication link between the first pair of network nodes and a second estimated link quality of a second communication link between the second pair of network nodes, and the relay communication path to use for communicating with the second network node is selected based on the first and second estimated link qualities.

7. The method of claim 6, the method further comprising: based on the first estimated link quality of the first communication link and the second estimated link quality of the second communication link, forming a first candidate relay communication path which includes the first communication link between the first pair of network nodes and a second candidate relay communication path which includes the second communication link between the second pair of network nodes, wherein determining the relay communication path to use for communicating with the second network node comprises selecting one of the first and second candidate relay communication paths.

8. The method of claim 7, whereinthe first candidate relay communication path comprises a first group of one or more communication links including the first communication link, the second candidate relay communication path comprises a second group of one or more communication links including the second communication link, the method comprises: determining a cost of transmitting and / or receiving data over each communication link included in the first group; summing up the costs of transmitting and / or receiving data over the communication links included in the first group; determining a cost of transmitting and / or receiving data over each communication link included in the second group; and summing up the costs of transmitting and / or receiving data over the communication links included in the second group, and one of the first and second candidate relay communication paths is selected based on a comparison of the sum of the costs for the first group and the sum of the costs for the second group.

9. The method of claim 5, wherein the information related to said at least one relay communication path indicates a list of candidate relay communication paths between the first and second network nodes and a cost of transmitting and / or receiving data over each candidate relay communication path included in the list, and determining the relay communication path to use for communicating with the second network node comprises selecting a relay communication path included in the list based on the costs.

10. The method of claim 9, wherein each candidate relay communication path included in the list is formed by the model node based on an estimated link quality of a communication link between each of a plurality of pairs of network nodes included in the first network node, the second network node, and the candidate group of relay network nodes, andthe link quality of the communications link between each of the plurality of pairs of network nodes is estimated by the model node based on a simulation of operations of the plurality of pairs of network nodes in the virtual representation of the network environment.

11. The method of claim 5, wherein the information related to said at least one relay communication path indicates the relay communication path to use for communicating with the second network node.

12. The method of claim 10, wherein the relay communication path to use for communicating with the second network node is selected from a list of candidate relay communication paths formed by model node in the virtual representation of the network environment, and the list of candidate relay communication paths is formed by the model node based on estimated link qualities of communication links between each of a plurality of pairs of network nodes included in the first network node, the second network node, and the candidate group of relay network nodes.

13. A method (600) performed by a model node (114) for establishing a relay communication path between a first network node (112) and a second network node (102), the method comprising: simulating (s602) operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located; based on a result of the simulation, determining (s604) information related to at least one relay communication path between the first network node and the second network node; and transmitting (s606), to the first network node, the information related to said at least one relay communication path between the first network node and the second network node.

14. The method of claim 13, wherein the virtual representation of the network environment is a digital twin, DT, of the network environment.

15. The method of claim 13 or 14, wherein the simulating comprises simulating operations of at least one pair of network nodes included in the first network node, the second network node, and the candidate group of network nodes in the virtual representation of the network environment, and based on a result of the simulation of the operations of said at least one pair of network nodes, estimating a link quality of a communication link between said at least one pair of network nodes, wherein the information related to said at least one relay communication path is determined based on the estimated link quality of the communication link between said at least one pair of network nodes.

16. The method of claim 15, wherein said at least one pair of network nodes includes a first pair of network nodes and a second pair of network nodes, and estimating the link quality of the communication link between said at least one pair of network nodes comprises: estimating a first link quality of a first communication link between the first pair of network nodes; and estimating a second link quality of a second communication link between the second pair of network nodes.

17. The method of claim 16, wherein the information transmitted from the model node to the first network node indicates the estimated first link quality of the first communication link and the estimated second link quality of the second communication link.

18. The method of claim 16, the method comprising: based on the first estimated link quality of the first communication link and the second estimated link quality of the second communication link, forming: a first candidate relay communication path which includes the first communication link between the first pair of network nodes; anda second candidate relay communication path which includes the second communication link between the second pair of network nodes.

19. The method of claim 18, the method comprising: determining a first cost of transmitting and / or receiving data over the first candidate relay communication path; and determining a second cost of transmitting and / or receiving data over the second candidate relay communication path.

20. The method of claim 19, wherein the first candidate relay communication path comprises a first group of two or more communication links including the first communication link, the second candidate relay communication path comprises a second group of two or more communication links including the second communication link, the method comprises: determining a cost of transmitting and / or receiving data over each communication link included in the first group; summing up the costs of transmitting and / or receiving data over the communication links included in the first group, thereby determining the first cost; determining a cost of transmitting and / or receiving data over each communication link included in the second group; and summing up the costs of transmitting and / or receiving data over the communication links included in the second group, thereby determining the second cost.

21. The method of claim 19 or 20, wherein the information transmitted from the model node to the first network node indicates: the first candidate relay communication path; the second candidate relay communication path; the first cost; andthe second cost.

22. The method of claim 19 or 20, the method comprising: selecting one of the first and second candidate relay communication paths based on a comparison of the first cost and the second cost, wherein the information transmitted from the model node to the first network node indicates the selected candidate relay communication path.

23. A computer program (700 or 800) comprising instructions (744 or 844) which when executed by processing circuitry (702 or 802) cause the processing circuitry to perform the method of any one of claims 1-22.

24. A carrier containing the computer program of claim 23, wherein the carrier is one of an electronic signal, an optical signal, a radio signal, and a computer readable storage medium.

25. A first network node (112) for finding a relay communication path to use when communicating with a second network node (102), the first network node being configured to: obtain (s502) information related to at least one relay communication path between the first network node and the second network node, wherein the information related to said at least one relay communication path is determined based on a simulation of operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located; and based on the information related to said at least one relay communication path, determine (s504) the relay communication path to use for communicating with the second network node.

26. The first network node of claim 25, wherein the first network node is further configured to perform the method of any one of claims 2-12.

27. A model node (114) for establishing a relay communication path between a first network node (112) and a second network node (102), the model node being configured to:simulate (s602) operations of the first network node, the second network node, and a candidate group of relay network nodes in a virtual representation of a network environment in which the first network node, the second network node, and the candidate group of relay network nodes are located; based on a result of the simulation, determine (s604) information related to at least one relay communication path between the first network node and the second network node; and transmit (s606), to the first network node, the information related to said at least one relay communication path between the first network node and the second network node.

28. The model node of claim 27, wherein the model node is further configured to perform the method of any one of claims 14-22.

29. An apparatus (700 or 700) comprising: a processing circuitry (702 or 802); and a memory (741 or 841), said memory containing instructions executable by said processing circuitry, whereby the apparatus is operative to perform the method of any one of claims 1-22.

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