5G-Blueprint aims to design and validate a technical architecture and business and governance models for uninterrupted cross-border teleoperated transport based on 5G connectivity. The teleoperated transport element of the project is divided into several use cases and several enabling functions. But also the 5G contributions of this project can be divided into multiple 5G topics.
Information about the deployed network infrastructure in the pilot sites, and the corresponding architecture, can be found in deliverable “D5.2 Initial report on the 5G network deployment”. Chapter 2 of that document contains information regarding the architecture; sections 4.2, 4.3 and 4.4 introduce the deployed network infrastructure.
Combining URLLC and eMBB in a cross-border setting
One of the main innovations of 5G technology is that the network can be configured in such a way that it can support different types of communication at the same time, even if these have conflicting requirements when it comes to the tradeoff between bandwidth, latency and reliability. Two of these different types of communication are Ultra Reliable Low Latency Communication (URLLC), and enhanced Mobile Broadband (eMBB). While URLLC solutions sacrifices throughput capacity to shorten latency and improve reliability, eMBB in general does the opposite. However, the form of direct control teleoperation validated in this project requires the combination of both: several HD video streams need to be communicated from the truck or vessel to the remote operator station, consuming significant amounts of bandwidth (eMBB), but at the same time requiring low latency and high reliability (URLLC) to allow remote control of the vehicle or vessel. That is a challenging combination, and the pilot activities of the teleoperation use cases will validate how 5G technology can realize it. And to add one more element to this challenge, this will be done in a cross-border setting with vehicles and vessels crossing the Dutch-Belgian border at Zelzate, hence introducing the need to also support seamless roaming for safe teleoperation.
Bandwidth and reliability at port terminal
A port terminal is a quite challenging environment for a wireless network. Container stacks or large (container) ships passing by are large metal obstructions that can very dynamically influence the actual coverage characteristics of the deployed 5G radio infrastructure. The project will validate in its pilots of both teleoperation use cases but also the container ID recognition enabling function how 5G technology can cope with these circumstances. It will also look at one specific innovative solution to this challenge as part of the pilot of the enabling function on scene analytics. In that case it will be validated how a private small cells with RAN and MEC capabilities can be deployed by the site owner and integrated in the public network of the mobile network operator.
Fixed wireless access for critical infrastructure
In the past, critical infrastructure such as traffic lights has been typically connected to the central systems of the road operator using wired connectivity. Doing the same using mobile network technology has not yet become mainstream, because even if that mobile network supports the imposed connectivity requirements in general, it cannot guarantee that it will remain able to do so in extraordinary network saturation conditions. However, through its slicing capabilities, 5G would be able to provide these guarantees for the first time. This concept of using 5G for fixed wireless access for critical infrastructure is validated in the project through the intelligent Traffic Light Controller enabling function.
Even though 5G technology provides higher capacity compared to its predecessors, it is valuable for any application on top to still consider the utilized mobile network connection as a valuable resource. Therefore making the application aware of the currently available capacity in the 5G network, and having it change its behavior based on that network awareness (e.g. by temporarily reducing resolution or framerate of a video stream when the network is becoming saturated) is an important element of any 5G-based solution. This concept is validated in the teleoperation use cases, but also in enabling functions such as e.g. distributed perception.
Multiple slices on same User Equipment
Through the concept of slicing, 5G technology can offer mobile connectivity with quite different performance characteristics to User Equipment (UE) using the same physical infrastructure. A straightforward manner to make sure the UE uses the appropriate slice is to equip it with a SIM card that is pre-configured to make use of a specific slice on the 5G network of the corresponding mobile network operator. However, this only works when this UE only has one specific set of connectivity requirements for all applications that it will run. Because then there is one slice to always connect to. However, some UE will run applications with different connectivity requirements. A smartphone is a good example of this: video or audio streaming requires a certain bandwidth to be provided, but because of the internal buffering of the media at the UE the requirements regarding reliability or latency are quite relaxed. However, cloud gaming applications on the other hand combine the same bandwidth requirements with much more stringent latency and reliability requirements. While an application exchanging data with a back-end to improve traffic safety has much lower bandwidth requirements but stringent latency and reliability requirements. As a result, on such an UE it should be able to connect to multiple slices at the same time using the same SIM card, and to have every application make use of the appropriate one. This part of the 5G solution suite will be validated as part of the pilot activities regarding the enabling function called vulnerable road user interaction.
Multi-access edge computing
Compared to using cloud computing services to host application logic, the Multi-Access Edge Computing (MEC) capabilities of 5G enable to host this logic closer to where the clients of the service are located. This allows to reduce latency, and to avoid saturation of the core network at its central break-out points to the Internet. In the pilot activities of the enabling function container id recognition this aspect of 5G will be validated.
Evaluating the performance of the 5g network
Within the 5G-Blueprint project, a comprehensive evaluation of the 5G network performance is conducted, with a primary focus on three designated trial locations: the cross-border site between Zelzate in Belgium and Sas van Gent in the Netherlands, the Belgian trial site situated at the Port of Antwerp, and the Dutch trial site located at Vlissingen. The overarching goal is to assess the efficacy of various 5G network deployments in meeting specified use cases and enabling function requirements. At the beginning of the project, a list of 5G network Key Performance Indicators (KPIs) were created through a consortium-driven iterative process. These KPIs form the basis for the subsequent technical evaluation of 5G network performance.
Methodology and tools
To perform the 5G evaluation within the 5G-Blueprint project, several tools were developed and used following a well-defined methodology.
Starting from standard and established conformance and interoperability testing methodologies, one of the first steps is to identify the potential location of Points of Control and Observation (PCOs) in the system under test where measurements will be taken.
Based on the location of the PCOs, the type of measurements that have been performed can be differentiated as follows:
- Application-level measurements: these end-to-end measurements focus on the performance that is perceived by the users and its applications, and as such the logging of the data is being conducted at the application level.
- Network segment measurements: these measurements are obtained by using logging data in the functional 5G network segments, for which the PCOs can be located at the endpoints and intermediate network segments at the transport layer or access layer.
5G system under test
An advanced set of tools was used to perform the measurements and evaluation of the list of networking KPIs according to the defined test plan. On top of some well-known open-source network measurement tools (such as IPerf and ping), IMEC developed its proprietary tools to allow for real-time logging of the tests in a structured way. Moreover, some in-house developed tools were implemented to measure one-way latency, packet delivery rate (PDR) and reliability.
The IMEC tools support both offline local logging, as well as real-time storing via 4G of logdata into a central MySQL database, to speed up the post-processing analysis. Well-defined CSV log formats were created for all metrics that are logged offline. Furthermore, within the database, several tables were created to store all logdata in a structured way.
To visualize the logged data from the tests that reside in the database, Grafana dashboards were implemented. Using Grafana, several statistics taken from the measured logdata are calculated and can be presented to the user in a graphical (in graphs and maps) and interactive/intuitive way, allowing the selection of e.g. test IDs, start and end times, etc.
For some of the KPIs (one-way latency, PDR, reliability), dedicated Python post-processing scripts were written by IMEC to retrieve the data from the database, make the necessary calculations and visualize the results in graphs.
E2E network test methodology
Seamless 5G Standalone roaming
Vehicular teleoperation is a step towards autonomous driving and other advanced Cooperative, Connected and Automated Mobility (CCAM) use cases. It is a promising alternative for road transport and logistics, especially with the current labor shortages affecting multiple industries. However, to enable such mission-critical use cases, 5G connectivity should satisfy stringent latency requirements and remain un-interrupted. This task is more challenging in a cross-border roaming scenario where the vehicle must be handed over to the network of a different operator in a different country.
5G Blueprint seamless roaming solution is the first practical implementation of seamless 5G SA roaming. It combines procedures from the 16th Release of the 3GPP specifications (Home-Routed Roaming and N14 Handover) with further novel optimizations to reduce downtime. The red lines in the figure show the interfaces (N9, N14 and N16) that TNO has developed during the project to obtain this goal.
The proposed solution was first built and validated in a lab setup at TNO which consists of two machines, each running the TNO extended 5G SA core, two off-the-shelf gNBs: Ericsson (provisioned by Telenet) and Huawei (provisioned by KPN), and a 5G User Equipment (e.g., Quectel or Sierra Wireless 5G modem, or a smartphone). Two attenuators are used to attenuate the signals from the gNBs. This way, we mimic cross-border scenarios (e.g., a car moving away from the coverage area of MNO1 to the coverage area of MNO2).
The results show that the usage of Seamless 5G SA roaming significantly reduces the average downtime: from 14s (which was the minimum achieved in 5G-MOBIX) to less than 100ms (see table).
|Mean UL downtime
|Mean DL downtime
In the cross-border trials, the same 5G SA cores and gNBs from the lab are used. The trial tests consist of a vehicle driving across the border a number of times to collect measurements for Round Trip Time, Signal Strength, downtime and throughput for both uplink and downlink.
Our field results show no significant deviation from the lab results. With an average downtime of around 110ms, our proposed solution meets the latency requirements of tele-operated driving services.
Physically, the two roaming-enabled TNO 5G SA cores were deployed at two different locations (one from KPN, and one from Telenet) and connected via an VPN.
The radio deployment at the border, provided by Telenet and KPN
Radio deployment by Telenet at the Belgian site of the cross-border area is twofold:
- Production site in the center of Zelzate, connected to the stand-alone (SA) and the non-standalone NSA core
- Mobile site at the border with the Netherlands, connected to the TNO SA core
When driving between the Netherlands and Belgium, the 5G modem in the vehicle was seamlessly roaming from Telenet to KPN and vice versa. In the following figure, the handover point is shown for a test run that was conducted.
In the dashboard below, the interruption time during a seamless handover is shown.
Belgian test site
In the following figure, an overview is shown of the 5G SA deployment in the port of Antwerp area by Telenet. This area was used to evaluate the 5G SA performance to accommodate for the use cases and enabling functions that are considered within the project. Tests have been performed both on the waterway (right bank and Schelde) and the road near the right bank. Furthermore, the area near Roossens was assessed to get insights into the 5G performance for the studied milk run between Roossens and Medrepair.
Telenet 5G deployment at the Belgian site
Dutch test site
In the Netherlands, two types of 5G deployments were realized. At the Vebrugge-Scaldia terminal in Vlissingen, KPN deployed a 5G SA network to cover the terminal area, which is shown in the figure below. The 5G SA performance in the area was evaluated in depth to get a thorough understanding of how 5G can accommodate the use cases and enabling functions in that area.
5G SA test area at Verbrugge Scaldia terminal
Furthermore, the 5G NSA network deployed by KPN in the Vlissingen area was assessed in terms of performance for the use cases targeting the MSP Onions and Kloosterboer terminals. In addition, the 5G performance to accommodate the milk runs near these terminals was evaluated, providing the results of the KPIs that were obtained during several measurement campaigns.
5G NSA test area at Vlissingen