Method for determining the virtual topology of a wireless bridge in a communication system, communication system

Abstract

The invention relates to a method for determining a topology of a TSN model of a wireless bridge handling a set of user equipments (UEs), where groups of user equipments are determined, each group being formed of UEs with contention access to time resources, and UEs of different groups are independent in terms of performance when activated simultaneously, and a topology of main blocks is constructed and provided to a centralized network configuration node. The topology includes N network side ports with which the network ports are associated with corresponding groups of UEs, P device side ports with which the device side ports are associated with corresponding UEs, and P internal links connecting the device side ports with which the internal links are associated with UEs of a given group with the network side ports associated with the given group. The invention further relates to a corresponding communication system and a corresponding computer program.

Description

Technical Field

[0001] The present disclosure relates to the field of telecommunication.

Background Art

[0002] More particularly, the present disclosure relates to a method for determining the topology of a time-sensitive network model of a wireless bridge of a communication system within a time-sensitive network. The present disclosure also relates to a corresponding communication system and a corresponding computer program.

[0003] The present disclosure addresses the problem of using a 5G network as a communication means for a time-sensitive network (TSN). The time-sensitive network was originally developed to provide communication with guaranteed delivery time on industrial Ethernet wired networks.

[0004] According to the convention in the current TSN standard, when flowing through a TSN bridge, the end-to-end delay is calculated by taking into account the aggregated delay of the transport links between the upstream bridge (external link) on the path and the internal link of the bridge between the input (ingress) port and the output (egress) port. In a normal TSN network, these aggregated delays are considered in a central scheduler that guarantees that packet collisions do not occur on the transport link in the time domain, or in a central network configuration node (CNC).

[0005] In a one-to-many bridge, the bottleneck lies in the external transport link to which the TDMA (Time Division Multiple Access) strategy is applied as a result of CNC scheduling. While the bridge's internal links can be used simultaneously, these internal links are actually used sequentially on the input transport link as a result of TDMA. The impact on performance is minor when the capacity of the internal links is much larger than the capacity of the transport link. However, the convention of considering aggregated delays induces significant performance degradation when the capacity of the internal links is comparable to or smaller than the capacity of the external links. Indeed, bridge capability is limited by not utilizing the possibility of simultaneous use of internal links.

[0006] Such a situation arises when considering a 5G TSN bridge where the internal link capacity is related to the wireless transmission capacity, which is generally inferior to the input link capacity that relies on wired Ethernet. Using the latest models available today and representing 5GS as a one-to-many topology, the TDMA strategy is applied to all packets flowing through the 5G TSN bridge. Unfortunately, TDMA is often not the best multiplexing scheme for wireless networks, as other multiplexing dimensions can be utilized with improved performance. Examples of multiplexing dimensions include frequency (using several subbands in the frequency domain), space (using multiple antennas), and site (frequency reuse between several non-interfering sites). Therefore, the latest definition of the model for a 5G TSN bridge does not utilize the multiplexing capabilities of 5GS, and as a result, its performance is suboptimal.

[0007] The time multiplexing capability of 5GS is often considerably lower than that of fixed Ethernet networks. For example, the smallest time unit in 5GS is a slot lasting at least 100 microseconds, while the maximum frame duration on a Gigabit Ethernet link is approximately 12 microseconds. Therefore, the low time granularity of 5GS is taken into account in the declaration of independent delay as a trade-off for any frame transmission. This is necessary because dependent and independent delays are used in CNC to calculate the guaranteed delay. However, 5GS inevitably relies on a radio interface that enables broadcasting. This means that several data flows can be transmitted simultaneously with variable capacity depending on the configuration, terminal location and channel state, the number of data flows sharing the radio channel simultaneously, etc. This multiplexing capability of 5GS is not inherently considered when considering the latest 5GS TSN bridge representations at present. Indeed, according to this bridge model, CNC provides packets at the bridge input in TDMA format according to the low internal time granularity of 5GS. [Overview of the project] [Problems that the invention aims to solve]

[0008] To improve the system performance of wireless bridges such as 5GS, utilize their system redundancy capabilities, and compensate for their low time granularity, it is necessary to design better TSN bridge models for such wireless bridges.

[0009] This disclosure aims to improve this situation. [Means for solving the problem]

[0010] A method for determining the virtual topology of a wireless bridge of a communication system in a time-sensitive network, wherein the wireless bridge handles a set of P user devices (UEs), and the communication system further comprises a centralized network configuration node, and the method is: The process involves constructing a virtual topology of a wireless bridge, where the virtual topology includes at least a main block, and the main block is: N network-side ports, each network-side port associated with a corresponding group of user devices handled by a wireless bridge having non-independent perceived quality, P device-side ports, where each device-side port is associated with a corresponding user device, N independent channels, each independent channel connecting a device-side port associated with a given group of user devices to a network-side port associated with the given group, Including, To provide the virtual topology of the wireless bridge to the centralized network configuration node, A method including this is proposed.

[0011] The main blocks represent UE deployments as separate groups. N and P are natural numbers, N is at least equal to 2, and each group contains at least one user device.

[0012] Non-independent perceived quality relates to conflicting access to a set of physical channels used by the wireless bridge as a resource for handling a set of UEs. UEs having conflicting access to the aforementioned set of physical channels are grouped together. Conversely, UEs having non-conflicting access to the aforementioned set of physical channels are considered separately as part of different groups. For example, UEs having conflicting access to a temporal resource may be grouped together due to a lack of orthogonality in other dimensions of multiplexing (e.g., no orthogonality in spatial or frequency multiplexing), while UEs without conflicting access to a temporal resource may belong to different groups.

[0013] The virtual topology of the wireless bridge illustrates this particular division of a set of UEs into groups, because UEs in a given group are considered accessible together through a common network-side port, while UEs in different groups are represented as accessible through separate data paths with different network-side ports.

[0014] In this regard, by providing the CNC with a virtual topology of the wireless bridge, it becomes possible to utilize the multiplexing capabilities of the wireless bridge.

[0015] In particular, by providing the topology of the main blocks, data packets can be interpreted by the CNC as arriving at different network ports, possibly simultaneously. The result is that data transmission in 5GS does not need to systematically follow the TDMA method.

[0016] Providing the topology of the main blocks to the CNC is equivalent to providing the CNC with knowledge about the multiplexing capabilities of the wireless bridge in dimensions other than the time dimension. Providing a virtual topology of the wireless bridge model may include providing a pair of guaranteed delays associated with each independent channel, including a dependent delay and an independent delay, both set to non-zero values.

[0017] This allows the CNC to better utilize the wireless bridge's multiplexing capabilities and reduce end-to-end latency by determining TSN schedules with simultaneously activated UEs from different groups without causing performance loss.

[0018] The above methods are understood to be carried out by computer means. Different functional entities may be defined in this regard. For example, dividing a set of P user devices as defined above is performed by one or more processors executing one or more centripetal instructions. Thus, division can be considered conceptually as a task affected by a computational entity called a “division module” or “grouping module”. Similarly, topology construction is a task assigned to a computational entity called a “topology construction module”. Naturally, the division module and topology construction module may be hosted by the same physical entity, such as a processor, or by different physical entities without distinction. Topology provision is a task assigned to a computational entity called a “topology provision module” that controls the communication interface.

[0019] In another embodiment, computer software or a program is proposed which includes one or more instructions that, when the software is executed by a processor, perform at least a part of the method as defined herein. In another embodiment, the software is proposed which is a computer-readable non-temporary recording medium that is registered to perform the method as defined herein when the software is executed by a processor.

[0020] In another embodiment, a communication system in a time-sensitive network, the communication system comprising a wireless bridge for handling a set of P user devices (UEs), the communication system further comprising a centralized network configuration node, the communication system The process involves constructing a virtual topology of a wireless bridge, where the virtual topology includes at least a main block, and the main block is: N network-side ports, where the network-side ports are associated with corresponding groups of user equipment handled by a wireless bridge having non-independent sensing quality, the N network-side ports, P device-side ports, where the device-side ports are associated with corresponding user equipment, the P device-side ports, N independent channels, where the independent channels connect the device-side ports associated with a given group of user equipment to the network-side ports associated with the given group, the N independent channels, including, providing a virtual topology of a wireless bridge model to a centralized network configuration node, A communication system configured to perform is proposed.

[0021] The following features can be implemented optionally, separately or in combination with each other.

[0022] The wireless bridge includes n physical network-side ports, The virtual topology can further include a demultiplexing block, and the demultiplexing block, n network-side ports, N device-side ports, N internal links, where the internal links connect the device-side ports to the network-side ports, the N internal links, including, The device-side ports of the demultiplexing block are associated with the corresponding network-side ports of the main block.

[0023] The main purpose of the demultiplexing block is to enable the virtual topology to be interpreted as having a single common network-side port for all data flows circulating through the wireless bridge.

[0024] In this context, providing a virtual topology for the wireless bridge model involves providing, for each internal link in the demultiplexed block, a pair of guaranteed delays associated with the internal link, including a dependent delay and an independent delay. Both delays can be favorably set to zero.

[0025] A group can be formed within a set of P user devices according to predetermined criteria. These criteria may relate to the access of a set of user devices to a set of physical channels used by a wireless bridge to handle the set of user devices.

[0026] In fact, the results of the splitting will vary depending on the various possible deployments of the user equipment set and the various deployments of the base stations, and in particular, on the multiplexing capability of the wireless bridge for each such deployment.

[0027] The group When a user device is activated, it is involved in the transmission of at least one data flow through the wireless bridge. Dataflow performance is related to a given dataflow among at least one dataflow, For any first subset of user devices belonging to the same group of user devices, simultaneous activation of any user device in the first subset degrades data flow performance for at least one given user device in the first subset, selected from among the simultaneously activated user devices in the first subset, compared to the case where a given user device in the first subset is activated alone. For any second subset of user devices belonging to different groups, simultaneous activation of any user device in the second subset does not degrade data flow performance for any given user device in the second subset, selected from among the simultaneously activated user devices in the second subset, compared to the case where a given user device in the second subset is activated individually. It can be formed in this way.

[0028] When the difference in data flow performance between concurrent activation and single activation exceeds a predetermined threshold, data flow performance is said to be "degraded." The predetermined threshold may be an absolute threshold or a relative threshold.

[0029] In the example above, any number of user devices within the same group of user devices will have conflicting access to the time resource, while any number of user devices acquired from different groups of user devices will not have conflicting access.

[0030] The group can be formed based on indications related to the multiplexing capability at one or more base stations for the deployment of user equipment.

[0031] As further demonstrated, indicators related to multiplexing capability can be of various natures and sources. For example, indicators related to multiplexing capability may include RAN-level information and / or end-to-end QoS KPI measurements at the application layer for various activation topologies.

[0032] In one example, a wireless bridge may include multiple base stations, each handling at least one corresponding user device, and the groups may be formed such that any user devices belonging to the same group are handled by the same base station, based on an indication of which base station handles each user device.

[0033] Even if user equipment is handled by the same base station, it is still possible for it to belong to different groups.

[0034] For example, a wireless bridge may comprise a given base station that handles a subset of a set of P user devices by orthogonalizing the transmission of the subset of user devices in a multi-antenna spatial dimension. The groups may then be configured such that any user device in a subset belonging to the same group is handled by the same antenna of the given base station, based on the indication of the antenna used by the given base station to handle each user device in the subset.

[0035] In the example above, the indication regarding multiplexing capability is RAN level information related to spatial and frequency multiplexing.

[0036] Furthermore, the wireless bridge may include a given base station that handles two given user devices by orthogonalizing transmissions to those two user devices through a semi-static resource allocation scheme. In this case, the groups can be formed so that the two given user devices are assigned to different groups based on the indication of the allocation scheme.

[0037] This example demonstrates a method that utilizes the time-frequency multiplexing capability of a wireless bridge.

[0038] The multiplexing capability of a wireless bridge may be asymmetric, meaning that the uplink and downlink may exhibit different properties.

[0039] In this regard, non-independent perceived quality applies to data transfers that all have the same orientation, and the data transfer is, Downlink, defined as data transfer established from the wireless bridge to each user device, and Uplink is defined as data transfer established from each user device to the wireless bridge. It is one of the following: The virtual topology may be adapted to the above orientation of data transfer.

[0040] In other words, it is possible to construct two separate virtual topologies of the same wireless bridge, one optimized for uplink and the other for downlink. This possibility is made possible by the unidirectional nature of the delay provided to the CNC.

[0041] To do this, the method is to construct an additional virtual topology of a wireless bridge adapted to the opposite orientation, the additional virtual topology including at least a main block, and the main block is M network-side ports, each network-side port associated with a corresponding group of user devices handled by a wireless bridge having non-independent perceived quality applied in the opposite direction, P device-side ports, where each device-side port is associated with a corresponding user device, M independent channels, each independent channel connecting a device-side port associated with a given group of user devices to a network-side port associated with the given group, Including, To provide additional virtual topologies for wireless bridges to the centralized network configuration node, It can further include:

[0042] M is a natural number that may be equal to or different from N. For example, the virtual topology of a wireless bridge optimized for downlink can include not only N independent channels associated with finite delay, but also M additional independent channels (or M network-side ports) associated with infinite delay. Similarly, the virtual topology of a wireless bridge optimized for uplink can include not only M independent channels associated with finite delay, but also N additional independent channels associated with infinite delay. In this case, both virtual topologies contain the same number of N+M independent channels. Each of the above channels corresponds to the same equivalent virtual port pair in both virtual topologies, differing only by the value of the delay advertised to the CNC. In another example, one network port is associated with one independent downlink channel associated with a finite downlink delay and one independent uplink channel associated with a finite uplink delay, another network port is associated only with one independent downlink channel associated with a finite downlink delay and the corresponding delay in the uplink direction is set to infinite, and yet another network port is associated only with one independent uplink channel associated with a finite uplink delay and the downlink direction is associated with infinite delay.

[0043] Other features, details, and advantages are described in the following detailed explanation and diagrams. [Brief explanation of the drawing]

[0044] [Figure 1] This is a diagram illustrating an example of a TSN wireless bridge model according to one embodiment. [Figure 2] This is a diagram illustrating an example of a TSN network according to one embodiment. [Figure 3] This figure shows the delay calculation between two end stations via a TSN bridge according to one embodiment. [Figure 4] This figure shows gate opening and packet propagation along a data path according to one embodiment. [Figure 5]This is a diagram illustrating the latest representation of 5GS as a TSN bridge. [Figure 6] This is the latest representation of 5GS as a TSN bridge, and can be seen in the Ericsson Technology Review, 5G-TSN integration meets networking requirements for industrial automation, August 2019, Farkas, J.; Varga, B.; Miklos, G.; Sachs, J. [Figure 7] This is a diagram illustrating the latest representation of 5GS as a TSN bridge. [Figure 8] This figure shows spatial multiplexing and frequency multiplexing between different node base stations of a wireless bridge according to one embodiment. [Figure 9] This figure shows spatial multiplexing using multiple antennas at a node base station of a wireless bridge according to one embodiment. [Figure 10] This figure shows spatial multiplexing using multiple antennas at a node base station of a wireless bridge according to one embodiment. [Figure 11] This figure shows time-frequency multiplexing through static scheduling or slicing at a node base station of a wireless bridge according to one embodiment. [Figure 12] This is a diagram illustrating an example of a TSN wireless bridge model according to one embodiment. [Figure 13] This figure shows the deployment of a wireless communication system according to one embodiment. [Figure 14] This is an example of a TSN wireless bridge model of the wireless communication system shown in Figure 13, according to one embodiment. [Figure 15] This is a flowchart of a software implementation method for determining a suitable topology for the downlink of a TSN wireless bridge, according to one embodiment. [Figure 16] This is a flowchart of a software implementation method for determining a suitable topology for the uplink of a TSN wireless bridge, according to one embodiment. [Figure 17] This figure shows an example of a processing circuit suitable for executing the software shown in Figures 15 and 16, according to one embodiment. [Modes for carrying out the invention]

[0045] This disclosure involves clustering different user devices handled by a wireless bridge such that a given cluster regroups user devices where simultaneous activation leads to performance losses compared to sequential activation. Each user device belongs to a single cluster. Following this clustering, a main block 100 is then constructed.

[0046] The main block 100 includes network-side ports 10, 20, the same number as the cluster, and device-side ports 11, 12, 13, 21, 22, the same number as the user devices handled by the wireless bridge. The main block further includes one internal link per device-side port. These internal links are not shown individually in Figure 1.

[0047] Each cluster is associated with the corresponding network ports 10 and 20.

[0048] Each user device is associated with the corresponding device-side ports 11, 12, 13, 21, and 22.

[0049] For each given user device, a corresponding internal link with a finite capacity connects the device-side port 12 associated with the device to the network-side port 10 associated with the cluster including the device.

[0050] An example of a virtual topology 1000 including such a main block 100 is provided in Figure 1.

[0051] Each internal link is C' iIt has a capacity represented by . Here, "capacity" is used as a term that describes the ability of a wireless bridge to handle data and is associated with bandwidth. In a TSN network, capacity is translated into dependent delay and independent delay.

[0052] Figure 1 shows five internal links. - A first link between a first NW port and a first DS port having a capacity represented by C'1, - A second link between the first NW port and the second DS port having a capacity represented by C'2, - A third link between the first NW port and the third DS port, having a capacity represented by C'3, - A fourth link between the second NW port and the fourth DS port, having a capacity represented by C'4, - A fifth link between the second NW port and the fifth DS port, having a capacity represented by C'5.

[0053] The main block 100 provides an accurate description of the performance of the wireless bridge when user devices belonging to different clusters are activated simultaneously. By advertising such an accurately described performance of the wireless bridge to the Centralized Network Configuration (CNC) node of the time-sensitive network, the CNC can improve this performance. Examples of such improvements include increasing the number of supported TSN data streams and / or setting a reduced guaranteed delay for TSN data streams flowing through the 5GS bridge.

[0054] Figure 1 further shows a demultiplexed block 200, as an optional feature, having a single network-side port 210 and the same number of device-side ports 211, 212 as the number of network-side ports 10, 20 in the main block 100. The demultiplexed block 200 further includes an internal link with unlimited capacity for each device-side port 211, 212, connecting the device-side port to the network-side port 30.

[0055] The purpose of this demultiplexing block 200 is to allow the virtual topology 1000 of the wireless bridge to interface with another TSN bridge model 300 in a simple form.

[0056] This concerns the current state of affairs regarding intermediate TSN bridges interfaced with each other using a single network-side port.

[0057] This uniqueness can be maintained by representing any wireless bridge in a TSN network through a combination of the main block 100 and the demultiplexing block 200, where the device-side ports 211 and 212 of the demultiplexing block 200 are connected to the corresponding network-side ports 10 and 20 of the main block 100, respectively.

[0058] Next, the resulting virtual topology 1000 can interface with another TSN bridge 300 through the network-side port 210 of the demultiplexing block 200.

[0059] In the following, this disclosure will focus on downlink, which is transmission by a base station and reception by a terminal. Naturally, this disclosure also applies to uplink, and combinations of uplink and downlink.

[0060] <TSNネットワーク> This disclosure focuses on the transmission of packets with latency constraints. To achieve guaranteed end-to-end latency for packet transmission between a talker and a listener, it is necessary to rely on a given data path or route and the scheduling of the operation of network elements along that path.

[0061] According to the fully centralized model of IEEE 802.1Qcc, a TSN network includes several elements as shown in Figure 2.

[0062] In Figure 2, Talker 1 and Listener 2 are both represented as end stations (ES) of the TSN network. A series of TSN bridges 3 are further represented.

[0063] The TSN Bridge 3 is a packet-switching device in a TSN network. Packets arriving at the bridge's ingress port can be routed to the egress port in bounded delay according to several parameters specific to each port pair represented by the internal link. These parameters are typically a dependent delay coefficient (i.e., payload-dependent and can be considered the inverse of the link's instantaneous throughput) and an independent delay (i.e., a fixed delay per communication).

[0064] The TSN network further includes a centralized user configuration node (CUC) 4 configured to communicate with end stations 1 and 2 to receive flow requirements.

[0065] The TSN network further comprises a Centralized Network Configuration Node (CNC) 5. The CNC can receive exit and entry port identification information, traffic class, and QoS indicators as minimum and maximum latency per port pair from different TSN bridges.

[0066] CNC5 can also receive user configuration data from CUC4 and TSN Bridge 3 via the user / network interface. User configuration data may include end station flow requirements. User configuration data may further include the TSN network topology related to the end station flow requirements. User configuration data may further include the network link capacity based on the above topology.

[0067] The CNC5 that collects the topology, the capacity of the network links, and the requirements of the data stream as described above defines a routing decision, i.e., bridge selection, or in other words, a data path for transmitting packets from one end station 1 through bridge 3 to another end station 2. This data path is calculated by the CNC in a known manner to meet the stream requirements of the TSN flow.

[0068] With the consistent aim of meeting the stream requirements of the TSN flow, the CNC5 further calculates the scheduling of gate openings for packets to flow from one ES to another while guaranteeing the transmission delay. To do this, the CNC calculates the cumulative delay from the exit port to the exit port of two consecutive bridges in the calculated data path, where the exit port is defined at the output port of the bridge in the flow direction of the packet along the path (while the inlet port is the bridge input port).

[0069] The scheduling calculated in the CNC is a time gating window table according to which the gates are continuously opened and closed. In practice, for each bridge port, the packets are buffered and continuously transmitted when the corresponding gate opens. For this reason, time multiplexing is specific to each bridge port while simultaneous transmission is possible between two different ports of the TSN bridge.

[0070] <Description of the TSN bridge model> Figure 3 shows the definition of dependent delay and independent delay from the exit port of one bridge to the exit port of another bridge in the data path associated with a given data stream.

[0071] Three bridges 3 represented by Bn-1, Bn, and Bn+1 are shown on the data path.

[0072] More specifically, for a given bridge Bn, the inlet port indicated by i and the outlet port indicated by e are represented on the data path and form an oriented port pair.

[0073] For each pair of oriented ports, the dependent delay provided by bridge Bn is: - D corresponds to the cable bandwidth between the exit port of the previous bridge Bn-1 and the inlet port of Bn on the data path. c Delays represented by, - Corresponding to the internal bandwidth in Bn,

number

[0074] For each oriented port pair, provided by bridge Bn,

number

[0075] In addition, for each exit port of Bn, a propagation delay represented by TxPropagationDelay can be defined as the transmission delay in the cable between the exit port and the inlet port of Bn+1 on the data path.

[0076] Different streams can follow different data paths, each containing different oriented port pairs within the bridge Bn. The dependent and independent delays provided by the bridge Bn may differ for each oriented port pair, and the downstream propagation delay (TxPropagationDelay) may also differ for each exit port.

[0077] Figure 4 shows the open time of the bridge gate defined by the CNC for propagating a packet with packet size P along the data path.

[0078] Three consecutive time intervals 6, 7, and 8 are shown in Figure 4.

[0079] The first time interval 6 corresponds to the opening of the bridge gate in bridge Bn-1. During this time interval, bridge Bn-1 is enabled to transmit packets through its exit port located on the data path. The length of this time interval is calculated from the dependent delay provided by bridge Bn for the oriented port pairs on the data path, and from the packet size P.

[0080] The second time interval 7 begins at the end of the first time interval 6. - The propagation delay associated with the exit port of Bn-1 on the data path, -Independent delay provided by bridge Bn for oriented port pairs on the data path, It has a time length corresponding to the sum of the numbers.

[0081] Assuming that the packet transmission by bridge Bn-1 was successful during the first time interval, it is then guaranteed that the packet will be available at the exit port of bridge Bn by the end of the second time interval.

[0082] The third time interval 8 begins at the end of the second time interval 7 and corresponds to the opening of the bridge gate in bridge Bn. During this time interval, bridge Bn is enabled to transmit packets through its exit ports located on the data path. The length of this time interval is calculated from the dependent delay provided by bridge Bn+1 for the oriented port pairs on the data path, and from the packet size P.

[0083] As described above, the end-to-end delay between two end stations is calculated by taking into account the aggregated delay of the transport link between the preceding bridge (external link) on the path and the internal link of the bridge between the input (inlet) port and the output (exit) port. This is described in the 802.1Qcc standard as follows: "Length-dependent delay typically includes the time to receive and store each octet of a frame, and this time depends on the link speed of the inlet port. For example, when the inlet port is operating at 1 Gb / s, both dependentDelayMin and dependentDelayMax may return 8000. If an internal communication mechanism exists within the bridge architecture (i.e., in a repeater), the time of that mechanism is added to the frame-dependent delay. For example, if a 100 Mb / s serial link connects the inlet and exit ports, the preceding example with a 1 Gb / s link speed may return 88000 for both dependentDelayMin and dependentDelayMax." (Dependent delay is expressed in picoseconds according to the 802.1Qcc standard).

[0084] <Description of 5GS TSN Bridge Model> In the current state of integrating 5G systems (5GS) into TSN networks, 5GS is typically represented as a general TSN bridge with a one-to-many topology including ports / gates, as shown in Figure 5. Here, the bridge has one NW (network-side) port 10 and two DS (device-side) ports 11, 12. The internal structure of the 5GS bridge involves network-side converters (NW-TTs), which are elements of 5GS that create an interface between the TSN network and the 5G user plane (UP) on the 5G core network side, and device-side converters (DS-TTs), which create an interface between the 5G UP and the radio devices on the access network side. Optionally, several ports can be associated with one network-side converter.

[0085] A more complete view of the internal structure of 5GS is given in Figure 6. The main components of 5GC (5G Core Network) and 5G RAN (5G Radio Access Network) are represented in the form of nodes or functional entities.

[0086] In particular, a functional separation is observed between the control plane 50 and the user plane 60.

[0087] The control plane includes PCF (Policy Billing Function) and TSN-AF (Time-Sensitive Network Application Function), both of which consist of 5GC nodes 51 each.

[0088] The user plane includes a UPF (User Plane Function) for routing packets between the 5G-RAN and network (NW) ports. The user plane further includes a gNB (next-generation node base station) configured to communicate with the 5G-RAN, more specifically the UPF, and handle the UE (user equipment).

[0089] It is possible to consider a virtual TSN bridge in the user plane. Considering a given data path, a virtual TSN bridge is defined using an NW port and multiple DS ports, where, -The network port is handled by UPF. - Each DS port is connected to the corresponding UE, which is handled by the gNB.

[0090] The figure also illustrates the control elements of the TSN network in the form of CUC4 (Centralized User Configuration Node) and CNC5 (Centralized Network Configuration Node) connected to the 5GS control plane via TSN-AF.

[0091] In the control plane, the TSN application function (TSN-AF) calculates the capacitance parameters of the 5GS bridge internal links.

[0092] When considering end station 1 connected to the NW port of a virtual TSN bridge, and several end stations 2 connected to DS ports associated with 5GS UEs, it is natural to assume that each DS port and DS-TT is associated with each UE, as shown in the latest Figure 6. Figure 6 represents two 5GS bridges, each defined on the network side by one NW-TT and one UPF.

[0093] Next, as shown in Figure 7, the dependent and independent delays associated with the port pairs of the virtual TSN bridge are related to the UE radio link capacity in 5GS.

[0094] Figure 7 shows two consecutive TSN bridges on the data path. The downlink is considered as an example.

[0095] Representation 300 of the upstream TSN bridge B0300 indicates the inlet port 310 and the outlet port 320.

[0096] One of the exit ports 320 is connected to the inlet NW port 10 in the representation of the downstream virtual TSN bridge B as the main block 100 in the representation of the upstream TSN bridge B0 300. The representation of the virtual TSN bridge further includes at least two exit DS ports 11, 12. Each exit port 11, 12 is linked to the inlet port 10 via a corresponding internal link. The capacity of the internal links is represented by C1 and C2. In practice, the capacity of the internal links relates to the capacity of the wireless link between the gNB and the UE.

[0097] Since B's inlet port 10 buffers received packets using time multiplexing, and CNC opens the gate of B0's outlet port 310 to prevent packet collisions, packets are transmitted non-simultaneously through two internal links via B's outlet ports 11 and 12.

[0098] As a result, TDMA (Time Division Multiple Access) transmission of packets within 5GS is performed, imposed by the arrival of continuous packets at B0's upstream exit port 310. Therefore, capacities C1 and C2 can be declared as the capacities of each UE when activated independently in 5GS.

[0099] Unfortunately, TDMA is often not the best multiplexing scheme for wireless networks because other multiplexing dimensions such as frequency (using several subbands in the frequency domain), space (using multiple antennas), and site (frequency reuse between several non-interfering sites) can be utilized without performance loss. For this reason, the latest definitions of 5G TSN bridge models fail to fully utilize the multiplexing capabilities of 5GS, resulting in suboptimal performance.

[0100] <Determining the Dependent Group> The multiplexing capabilities of wireless bridges such as 5GS bridges are specified in order to construct a virtual topology 1000 of wireless bridges suitable for CNC5 to utilize wireless bridges under the 802.1Qcc standard.

[0101] Identifying the multiplexing characteristics of a wireless bridge other than time multiplexing corresponds to evaluating, in terms of performance, the possibility of simultaneous data transmission from and / or to different UEs in the time domain. Simultaneous data transmission is the transmission of data from and / or to different UEs handled by one or more gNBs of the wireless bridge during overlapping time. Conversely, continuous data transmission is the transmission of data from and / or to different UEs handled by one or more gNBs of the wireless bridge in a continuous (temporal) manner. In the following, a UE is said to be “activated” if it is involved in transmitting or receiving at least one data flow, and “not activated” otherwise.

[0102] In other words, identifying the multiplexing capabilities of a wireless bridge beyond time-multiplexing corresponds to determining whether communication with a particular UE involves competing access to wireless resources.

[0103] The multiplexing capability of a wireless bridge is, for example, - Known locations of base stations and UEs, - Known radio conditions between the base station and the UE, - Known base station scheduling configurations, and / or -Measurements regarding the performance of each data flow for multiple data flows transmitted through a wireless bridge, each using a different data path. It can be determined from this.

[0104] Next, the UEs handled by the wireless bridge are distributed into multiple groups based on the determined multiplexing capability of the wireless bridge.

[0105] Specifically, if the simultaneous activation of UEs degrades the performance of at least one data flow of at least one of those UEs compared to the data flow performance achieved when each of those UEs is activated individually and sequentially, then those UEs belong to the same group.

[0106] For any set of UEs belonging to different groups, their simultaneous activation does not degrade any dataflow performance compared to the dataflow performance achieved when each UE in that set is activated individually.

[0107] As already mentioned, the difference in performance between at least one data flow under simultaneous activation and continuous activation conditions may be obtained from data flow performance measurements rather than as a direct result of the wireless bridge topology analysis. The difference between such measurements can be automatically compared to a predetermined absolute or relative non-zero threshold to uniquely determine whether such a difference corresponds to a performance degradation.

[0108] We will consider several examples of UE configurations where simultaneous packet transmission does not degrade data flow performance at each UE, and therefore demonstrates multiplexing capabilities other than time-based multiplexing.

[0109] Figure 8 shows the arrangement of two UEs under two different gNBs, 101 and 102. Radio access networks are typically designed so that large interference is not observed on the downlink or uplink of neighboring gNBs. This can be achieved, for example, by using different frequency bands, controlling the power of the gNBs and UEs, and / or using a mixture of frequency / power control, known as inter-cell interference adjustment.

[0110] As a result, data transmission to any UE handled by the first gNB101 does not affect the performance of data transmission to any UE handled by the second gNB102. Such multiplexing capability belongs to frequency and spatial multiplexing, since the transmissions are isolated from each other due to the spatial configuration of the transmitter and receiver, and / or the orthogonality of the frequency band usage.

[0111] In this case, when distributing the UEs handled by the wireless bridge into multiple groups based on the determined multiplexing capability of the wireless bridge, for example, two groups of UEs can be formed. One group of UEs is formed from all UEs handled by the first gNB, and the other group of UEs is formed from all UEs handled by the second gNB. More generally, in this case, if additional multiplexing capability of the wireless bridge is specified, three or more groups of UEs can be formed. However, none of the formed groups of UEs can include both UEs handled by the first gNB101 and UEs handled by the second gNB102.

[0112] Figure 9 shows the arrangement of two UEs within the coverage of the same gNB101. This gNB is equipped with multiple antennas and generates, for example, multiple beams 111, 112. Different multi-antenna techniques, such as beamforming as shown in Figure 9, enable the orthogonalization of transmissions from several UEs in the multi-antenna spatial dimension. This means that the two UEs can use the same time-frequency resources without significant performance loss. Therefore, in this example, these two UEs can be distributed into two different groups of UEs.

[0113] In some cases, as shown in Figure 10, particularly when the UEs are spatially close to each other, it is not possible to orthogonalize the UEs through the multi-antenna technique.

[0114] Figure 10 shows the following three UEs. -The first UE connected to the first DS port 11 is handled by the gNB 101 using the first antenna which generates the first beam 111. - The second UE connected to the second DS port 12 is handled by the gNB 101 using the first antenna which generates the first beam 111. - The third UE connected to the third DS port 21 is handled by the gNB 101 using the second antenna which generates the second beam 112.

[0115] The first and second UEs are considered to be spatially close to each other, and therefore the gNB communicates with both of these UEs by using the same antenna.

[0116] Assuming that the first and second UEs are not orthogonalized, a first group of UEs including the first and second UEs can be formed, and a second group of UEs including the third UE can be formed, according to the group definition shown above, based on the multi-antenna spatial orthogonality given by the multi-antenna technique used in the base station and UEs.

[0117] Figure 11 shows two UEs connected to different DS ports 11 and 21 under the coverage of the same gNB 101. One strategy for the gNB is to semi-statically allocate a given allocation of radio resources to the active UE, regardless of the status of the active UE's traffic (i.e., before knowing whether packets are available for transmission). For example, semi-persistent scheduling can achieve such a result to guarantee QoS for guaranteed bit rate (GBR) traffic. As a result, their performance is independent regardless of the data traffic of each UE. In this case, the two UEs can be assigned to different groups of UEs, according to the group definitions shown above.

[0118] As shown in the example above, by analyzing the orthogonalization capabilities of placement and transmission associated with several UEs, it is possible to group UEs such that UEs belonging to the same group have competing access to radio resources (i.e., their performance affects each other when activated simultaneously), while any UE belonging to a different group is independent in terms of performance.

[0119] <Proposed TSN model for 5GS> Refer to Figure 1 here.

[0120] Once a group of UEs is formed and identified, it is possible to determine the main block 100 which indicates whether different UEs have conflicting access to wireless resources, or conversely, whether their simultaneous activation will affect data flow performance.

[0121] The topology of the main 100 blocks is as follows:

[0122] The main block 100 includes the same number of network ports 10, 20 as the number of identified groups of UEs. The main block 100 further includes the same number of DS ports 11, 12, 13, 21, 22 as the total number of UEs across all identified groups of UEs. The main block 100 further includes internal links between each network port and all UEs belonging to the associated group.

[0123] Alternatively, the main block 100 can be determined as one or more model parts per group of UEs, with each model part having only one NW port and the same number of internal link and DS ports as the number of UEs in the associated group.

[0124] As long as the configuration link between the network port associated with the group and the DS port associated with the UE is maintained, any configuration that integrates these model parts is possible.

[0125] The capacity of the internal links in the main block 100 can be learned through measurement, i.e., data packets are transmitted to any UE and the capacity or delay is measured. Note that UEs in the same group should be learned independently, meaning that the capacity obtained for a given internal link is the capacity when the corresponding UE is the only activated UE within the group of UEs to which it belongs.

[0126] External links reaching any inlet port of the main block 100 can be assumed to have zero dependent delay and zero independent delay.

[0127] The number of physical network ports that a 5G TSN bridge can have is not necessarily equal to the number of specified UE groups. Furthermore, the latest models of 5G TSN bridges often include a single network port. Therefore, it is necessary to be able to define a model that matches the physical topology of the 5G wireless bridge from an external perspective.

[0128] To match the physical port topology, optionally, a Demux bridge model 200 can be introduced, having a number of NW ports 210 corresponding to the number of physical NW ports of the 5G TSN bridge, and the same number of DS ports 211, 212 as the number of identified groups of UEs. The Demux bridge further includes internal links to NW ports for each DS port. These internal links have zero independent and dependent latency, which corresponds to infinite capacity. The external links have the characteristics of a physical interface linking the 5GS CN to the TSN network, which is typically an Ethernet interface.

[0129] A simplified example of a virtual topology 1000 is provided in Figure 12, which comprises a demultiplexing block 200 having one NW port and a main block 100, where B' and B are the Demux bridge and the main bridge, respectively.

[0130] 5GS has two degrees of multiplexing, each capable of supporting capacity C'i. Packets can reach B's inlet ports 10 and 20 simultaneously, i.e., packets can reach ports 10 and 20 separated by a time value dependent on B' inlet link bandwidth, thereby they can be considered simultaneous with respect to B with respect to their internal link capacity, which does not force TDMA transmission in 5GS.

[0131] As a result, the end-to-end delay for transmitting two identical packets from upstream bridge B0 to end stations associated with exit ports 11 and 21 of B is related to 1 / C'1 + 1 / C'2 when considering the most current models, whereas in the new model of this disclosure, it is related to 1 / min(C'1,C'2). Therefore, the multiplexing capability of 5GS is fully utilized and the end-to-end delay is reduced.

[0132] <Example> Figure 13 shows an example of a 5GS deployment with two gNBs 101 and 102, seven UEs, and one ES for each UE. Within each gNB, spatial multiplexing between groups of UEs is provided by relying on beamforming techniques, e.g., analog beamforming obtained using an antenna array. Two radio frequency chains are available in each gNB, and beams 111, 112, 121, and 122 can be activated simultaneously. For each gNB, the handled UEs are clustered in two groups (spatially separated) as defined above herein. UEs handled by different gNBs do not interfere with each other due to the gNBs being sufficiently far apart (spatial separation) or due to the gNBs using different frequency channels (frequency separation).

[0133] An example of the corresponding virtual topology 1000 is provided in Figure 14, having a main block 100 and a demultiplexing block 200.

[0134] The main block 100 has four inlet ports associated with the four groups described above, and seven outlet ports associated with the seven UEs described above.

[0135] The first inlet port is connected to a first UE and a second UE that simultaneously share the same time / frequency resources under the first beam 111 of the first node base station 101.

[0136] The second inlet port is connected to a third UE, which is handled by the second beam 112 of the first node base station 101, and does not observe any influence from other UEs.

[0137] The third inlet port is connected to a fourth UE, which is handled by the first beam 121 of the second node base station 102, and does not observe any influence from other UEs.

[0138] The fourth inlet port is connected to the fifth, sixth, and seventh UEs, which simultaneously share the same time / frequency resources under the second beam 122 of the second node base station 102.

[0139] <Application to uplink> Although the above example focuses on downlink, those skilled in the art can easily apply the same principle to uplink, where the inlet port is the DS port and the outlet port is the NW port.

[0140] Next, two different models are constructed for downlink and uplink.

[0141] In fact, uplink wireless access techniques can differ from downlink techniques.

[0142] As a result, different methods for grouping UEs may be obtained, and different capacity measurements may be obtained for the internal links of the bridge.

[0143] When considering uplinks in particular, the main block has the same number of ingress ports as the number of UEs handled by the wireless bridge's gNB, and the same number of egress ports as the number of groups of UEs.

[0144] Optionally, the exit ports of the main blocks are connected to the inlet ports of a multiplexed (Mux) model, each having a number of exit ports corresponding to the physical number of network ports of the 5G TSN bridge.

[0145] <Algorithms and Processing Circuits> Figure 15 is a flowchart representing the overall algorithm of a computer program that can be stored on a storage medium and / or carried as a signal, for the purpose of performing the method disclosed above to determine the topology of the time-sensitive network model of the wireless bridge of a communication system within a time-sensitive network, for downlink applications.

[0146] The algorithm involves forming N groups of user devices from a set of P user devices handled by a wireless bridge (S1), where N and P are both natural numbers greater than 1.

[0147] As already stated, when a user device is involved in the transmission of at least one data flow through a wireless bridge, the data flow performance is related to a given data flow of at least one data flow, and for any first subset of user devices belonging to the same group of user devices, the simultaneous activation of two or more user devices in the first subset degrades the data flow performance in the wireless bridge compared to the activation of a single user device between the first subsets, and for any second subset of user devices all belonging to different groups, the simultaneous activation of all user devices in the second subset does not degrade the data flow performance in the wireless bridge compared to the activation of a single user device between the second subsets.

[0148] Next, the algorithm includes constructing the topology of a time-sensitive network model of a wireless bridge (S2), the time-sensitive network model including at least a main block, the main block including N network-side ports, each network port associated with a corresponding group of user equipment handled by the wireless bridge, P device-side ports, each device-side port associated with a corresponding user equipment, and P internal links, each internal link connecting a device-side port associated with a given group of user equipment to a network-side port associated with a given group.

[0149] The algorithm ultimately includes providing the topology of a time-sensitive network model to the centralized network configuration nodes within the communication system (S3).

[0150] Figure 16 is a flowchart representing the overall algorithm of a computer program that can be stored on a storage medium and / or carried as a signal, for the purpose of performing the method disclosed above for uplink applications, which determines the topology of a time-sensitive network model of a wireless bridge of a communication system within a time-sensitive network.

[0151] The algorithm includes forming M groups of user devices within a set of P user devices (S4) such that the uplink data flow performance is related to the uplink data flow, which is defined as the transfer of data from each activated user device to the wireless bridge, and for any first subset of user devices belonging to the same group of user devices, the simultaneous activation of all user devices in the first subset degrades the uplink data flow performance at the wireless bridge compared to the activation of a single user device between the first subsets, and for any second subset of user devices all belonging to different groups, the simultaneous activation of all user devices in the second subset does not degrade the uplink data flow performance at the wireless bridge compared to the activation of a single user device between the second subsets.

[0152] Next, the algorithm includes constructing the topology of an uplink main block (S5), which includes M network-side ports, each network port associated with a corresponding group of user equipment handled by a wireless bridge; P device-side ports, each device-side port associated with a corresponding user equipment; and P internal links, each internal link connecting a device-side port associated with a given group of user equipment to a network-side port associated with a given group.

[0153] The algorithm ultimately includes providing a topology of uplink main blocks, or (more generally) a topology of a time-sensitive network model of a wireless bridge including such uplink main blocks, to a centralized network configuration node in the communication system (S6).

[0154] Figure 17 schematically represents a processing circuit 90 suitable for executing one or both of the above algorithms. This processing circuit includes a memory 92 for storing a computer program containing one or more of the above algorithms. This processing circuit further includes a processor 91 for accessing the memory and executing the computer program. This processing circuit further includes a processor-controllable communication interface 93 for transmitting at least one or more of the above topologies of the time-sensitive network model to centralized network configuration nodes in a communication system.

[0155] Of course, it doesn't matter whether processor 91 uses a single core or multiple cores to execute the computer program. Cloud computing technology can also be used, where the computer program runs across processors with multiple processing circuits.

[0156] <List of citations> Depending on the purpose, the following non-patent literature may be cited. - nplcit1: IEEE 802.1Q-2018, as found on https: / / 1.ieee802.org / tsn / 802-1q / ; - nplcit2: IEEE 802.1Qcc-2018, as found on https: / / 1.ieee802.org / tsn / 802-1qcc / ; - nplcit3: 3GPP (Registered Trademark) TR 23.734 V16.2.0 (2019-06), “Study on enhancement of 5G System (5GS) for vertical and Local Area Network (LAN) services; - nplcit4: 3GPP TS 23.501; - nplcit5: Ana Larranaga and al., Analysis of 5G-TSN Integration to Support Industry 4.0, Proceedings of the IEEE 25th International Conference on Emerging Technologies and Factory Automation (ETFA 2020); and - nplcit6: Mannweiler and al., Reliable and Deterministic Mobile Communications for Industry 4.0: Key Challenges and Solutions for the Integration of the 3GPP 5G System with IEEE Time-Sensitive Networking, ITG-Fachbericht 288: Mobilkommunikation, 15 - 16.05.2019。

Claims

1. A method for determining the virtual topology of a wireless bridge of a communication system in a time-sensitive network by computer, wherein the wireless bridge handles a set of P user devices, and the communication system further comprises a centralized network configuration node, and the method is: Constructing a virtual topology of the wireless bridge, wherein the virtual topology includes at least a main block, and the main block is N network-side ports, N < P, each network-side port is associated with a corresponding group of user devices handled by the wireless bridge, and user devices having conflicting access to a set of physical channels used as resources by the wireless bridge are grouped together in the same group, while user devices having non-conflicting access to the set of physical channels are grouped together in different groups, and the user devices within the same group share non-independent perceived quality related to end-to-end latency due to having the conflicting access, with N network-side ports. P device-side ports, each device-side port associated with a corresponding user device, N independent channels, each independent channel connecting the device-side port associated with a given group of user devices to the network-side port associated with the given group, Including, To provide the virtual topology of the wireless bridge to the centralized network configuration node, Methods that include...

2. The wireless bridge includes n physical network-side ports, The virtual topology further comprises a demultiplexing block, the demultiplexing block is n network-side ports where n < N, N device-side ports, N internal links, where each internal link connects a device-side port to a network-side port, Includes, The method according to claim 1, wherein the device-side port of the demultiplexing block is associated with the corresponding network-side port of the main block.

3. The method according to claim 1 or 2, wherein the group is formed within the set of P user devices according to predetermined criteria relating to the access of the set of user devices to a set of physical channels used by the wireless bridge to handle the set of user devices.

4. The method according to claim 3, wherein the group is further formed based on an indication relating to the multiplexing capability of one or more base stations for the deployment of user equipment.

5. The aforementioned group, When the user device is activated, it is involved in the transmission of at least one data flow through the wireless bridge. The data flow performance relates to a given data flow among the at least one data flow, For any first subset of user devices belonging to the same group of user devices, simultaneous activation of any user device in the first subset degrades the data flow performance of at least one given user device in the first subset, selected from among the simultaneously activated user devices in the first subset, compared to when a given user device in the first subset is activated alone. For any second subset of user devices, all belonging to different groups, the simultaneous activation of any user device in the second subset does not degrade the data flow performance of any given user device in the second subset, as is the case when a given user device in the second subset is activated individually, selected from among the simultaneously activated user devices in the second subset. The method according to claim 3, which is formed in such a way.

6. The wireless bridge includes a plurality of base stations, each handling at least one corresponding user device. The method according to claim 4, wherein the groups are formed such that any user equipment belonging to the same group is handled by the same base station, based on an indication of which base station will handle each user equipment.

7. The wireless bridge comprises a given base station that handles a subset of the set of P user devices by orthogonalizing the transmission of the subset to the user devices in the multi-antenna spatial dimension. The method according to claim 4, wherein the groups are formed such that any user equipment in the subset belonging to the same group is handled by the same antenna of the given base station, based on the indication of antennas used by the given base station to handle each user equipment in the subset.

8. The wireless bridge includes a given base station that handles two given user devices by orthogonalizing transmissions between the two given user devices connected to different device-side ports through a semi-static resource allocation scheme that semi-statically allocates a given allocation of wireless resources to active user devices, The method according to claim 4, wherein the groups are formed such that the two given user devices are assigned to different groups based on the indication of the semi-static resource allocation scheme.

9. The aforementioned non-independent perceived quality applies to data transfers that all have the same orientation, and the said data transfer is The downlink defined as the data transfer established from the wireless bridge to each user device, and The uplink defined as the data transfer established from each user device to the wireless bridge, It is one of the following: The method according to claim 1 or 2, wherein the virtual topology is adapted to the orientation of the data transfer.

10. Constructing an additional virtual topology of the wireless bridge adapted to the opposite orientation, wherein the additional virtual topology includes at least a main block, and the main block is M network-side ports where M < P, each network-side port is associated with a corresponding group of user devices handled by the wireless bridge having non-independent perceived quality applied in the opposite direction, P device-side ports, each device-side port associated with a corresponding user device, M independent channels, each independent channel connecting the device-side port associated with a given group of user devices to the network-side port associated with the given group, Including, To provide the additional virtual topology of the wireless bridge to the centralized network configuration node, The method according to claim 9, further comprising:

11. A communication system within a time-sensitive network, the communication system comprising a wireless bridge for handling a set of P user devices, the communication system further comprising a centralized network configuration node, the communication system Constructing a virtual topology of the wireless bridge, wherein the virtual topology includes at least a main block, and the main block is N network-side ports, N < P, each network-side port is associated with a corresponding group of user devices handled by the wireless bridge, and user devices having conflicting access to a set of physical channels used as resources by the wireless bridge are grouped together in the same group, while user devices having non-conflicting access to the set of physical channels are grouped together in different groups, and the user devices within the same group share non-independent perceived quality related to end-to-end latency due to having the conflicting access, with N network-side ports. P device-side ports, each device-side port associated with a corresponding user device, N independent channels, each independent channel connecting the device-side port associated with a given group of user devices to the network-side port associated with the given group, Including, To provide the virtual topology of the wireless bridge model to the centralized network configuration node, A communication system configured to perform the following actions.

12. A computer program, which, when executed by a computer, includes instructions causing the computer to perform the method according to claim 1 or 2.

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