Vehicle-to-Everything Services in 3GPP 5G Networks: An Empirical Analysis

5/6G vehicle-to-everything (V2X), particularly vehicle-to-network (V2N) communication, should provide real-time data transfer between vehicles and the cloud. In this paper, we evaluate the capability of direct commercial 5G V2N connectivity to support 5G V2X services. We perform real-world local and cross-country drive tests to measure key performance metrics such as throughput and endto-end latency. We use the measurements to determine whether the 5G V2N meets the 3GPP standard requirements for V2X services. We then assess the feasibility of V2X services based on compliance with related latency, and throughput thresholds. Finally, we derive the signal strength thresholds required to support V2X services with low-level and high-level automation, providing insights for future 6G development.

5/6G 车联网 (Vehicle-to-Everything, V2X)，特别是车辆到网络 (Vehicle-to-Network, V2N) 通信，旨在实现车辆与云端之间的实时数据传输。在本文中，我们评估了商用 5G V2N 直连在支持 5G V2X 服务方面的能力。我们通过在本地和跨国进行真实世界的驾驶测试，测量了吞吐量和端到端时延等关键性能指标。我们利用这些测量结果来判断 5G V2N 是否满足 3GPP 标准为 V2X 服务设定的要求。随后，我们基于其对相关时延和吞吐量阈值的符合程度，评估了 V2X 服务的可行性。最后，我们推导出了支持低级别和高级别自动化的 V2X 服务所需的信号强度阈值，为未来 6G 的发展提供了见解。

Introduction

As intelligent vehicle users increases and demanding applications increase, the requests for network connectivity and other cloudnative services increase. These services include but are not limited to navigation, route optimization, over-the-air updates, real-time alerts, infotainment, and leisure functionalities. The future softwaredefined vehicles have been foreseen to enable various services, applications, and innovations on automotive boards [6]. Most require large-scale data, access to effective artificial intelligence models, and back-end services. To enable reliable network access to the cloud, considerations have turned into vehicle-to-everything (V2X) service-oriented systems [20]. However, the capability of the current commercial 5G networks does not seem to meet the latency requirements [27]. In this paper, we address the service availability of commercial 5G for V2X service-oriented systems using empirical data and experimental methods.

Unlike regular smartphone users in more static conditions, vehicles require fast and stable network connections to ensure safety and security in transportation. Prioritizing the vehicular network traffic ensures that critical safety messages, collision, and weather warnings are transmitted immediately. In this context, leveraging cellular vehicle-to-everything (C-V2X) [7] communication technologies is required, with vehicle-to-network (V2N) integration playing a pivotal role in enabling reliable, real-time data exchange between vehicles and the cloud. As a result, Society of Automotive Engineers (SAE) Level 3 [10] and above benefits greatly from V2X with minimal downtime, latency, and continuous availability in vehicle autonomy and functionality. V2N is a type of C-V2X connectivity that allows vehicles to connect to the Internet and access cloud services through cellular networks using the Uu interface[7], which operates in the traditional mobile broadband spectrum. While time-critical actions, like collision avoidance, need to be handled onboard, non-time critical services, such as facilitating warning alerts and risk avoidance that support reliable information sharing require reliable V2N.

随着智能汽车用户的增多以及对应用需求的提升，对网络连接和其他云原生服务的请求也随之增加。这些服务包括但不限于导航、路线优化、空中下载 (OTA) 更新、实时警报、信息娱乐以及休闲功能。未来的软件定义汽车预计将在车载平台上催生各种服务、应用和创新 [6]。其中大多数服务都需要大规模数据、有效的人工智能模型以及后端服务的支持。为了实现可靠的云端网络接入，研究重点已转向面向服务的车联网 (V2X) 系统 [20]。然而，当前商用 5G 网络的能力似乎无法满足其时延要求 [27]。在本文中，我们利用实证数据和实验方法，探讨了商用 5G 网络在 V2X 面向服务系统中的服务可用性。

与处于相对静态环境下的普通智能手机用户不同，车辆需要快速且稳定的网络连接以确保交通运输的安全与保障。优先处理车载网络流量可以确保碰撞和天气预警等关键安全信息得到即时传输。在此背景下，利用蜂窝车联网 (C-V2X) [7] 通信技术成为必要，其中车辆到网络 (V2N) 的集成在实现车辆与云端之间可靠、实时的数据交换中扮演着关键角色。因此，国际汽车工程师学会 (SAE) L3 级 [10] 及以上的自动驾驶能极大地受益于 V2X 技术，因为它能以最小的停机时间、时延和持续的可用性来保障车辆的自主性和功能性。V2N 是一种 C-V2X 连接方式，它允许车辆通过蜂窝网络，利用在传统移动宽带频谱上运行的 Uu 接口 [7] 连接到互联网并访问云服务。虽然像碰撞避免这类时间关键性操作需要在车内处理，但那些支持可靠信息共享的非时间关键性服务，如预警和风险规避，则需要可靠的 V2N 连接。

The primary objective of our work is to determine the capability of direct 5G V2N to provide standard V2X services for vehicular users. Our main contributions are as follows:

1. V2N connectivity over dedicated vehicle-to-vehicle or vehicle-to-infrastructure: Related works [14, 15] have mostly focused on engaging local networks with vehicle-to-vehicle (V2V) or vehicle-to-infrastructure (V2I). We specifically examine the potential of commercial 5G V2N as a direct communication link to enable both V2N and V2V/V2I-assisted services. V2N uses existing cellular infrastructure to connect vehicles to the cloud, a more scalable solution than deploying dedicated V2V/V2I infrastructure.

2. Real-world 5G V2N capability against 3rd Generation Partnership Project (3GPP) [1] standards: We use real-world drive tests in three countries to measure the current 5G V2N performance. This provides a practical perspective on the capabilities and limitations of the existing 5G V2N services and highlights needed future developments.

3. Signal strength thresholds for automation zones: We propose reference signal received power (RSRP) coverage thresholds 𝛼 for low-level automation and 𝛽 for high-level automation within the coverage limit 𝛾 (Figure 1). These zones can inform vehicles about enabled V2X, such as platooning and safety alerts in low automation zones. High automation zones can support advanced, latency-sensitive services like remote driving and AI-aided decisionmaking via the vehicle-to-cloud continuum.

4. How vehicle mobility impacts signal strength: We assess how vehicle speed, environmental type, network deployment mode, and handovers influence signal strength. Our results indicate a need to improve network reliability, expanding the availability of 5G stand-alone (SA) and upcoming 6G access points in road areas. This will enhance connectivity for dynamic users amid varying vehicle speeds and handovers.

我们工作的主要目标是确定 5G V2N 直连为车载用户提供标准 V2X 服务的能力。我们的主要贡献如下：

1. 专注于 V2N 连接，而非专用的车对车或车对基础设施通信： 相关工作 [14, 15] 大多集中于利用车对车 (V2V) 或车对基础设施 (V2I) 的本地网络。我们专门研究了商用 5G V2N 作为直接通信链路，以同时支持 V2N 和 V2V/V2I 辅助服务的潜力。V2N 利用现有的蜂窝基础设施将车辆连接到云端，这是一种比部署专用 V2V/V2I 基础设施更具可扩展性的解决方案。

2. 对照第三代合作伙伴计划 (3GPP) [1] 标准，评估真实世界中的 5G V2N 能力： 我们通过在三个国家进行的真实驾驶测试来测量当前 5G V2N 的性能。这为现有 5G V2N 服务的能力和局限性提供了实践性视角，并指出了未来需要改进的方向。

3. 为自动化区域定义信号强度阈值： 我们在覆盖范围极限 \(\gamma\) 内，为低级别自动化和高级别自动化分别提出了参考信号接收功率 (RSRP) 的覆盖阈值 \(\alpha\) 和 \(\beta\)（如图1所示）。这些区域划分可以告知车辆已启用的 V2X 服务类型，例如在低级别自动化区域内支持车辆编队和安全警报。高级别自动化区域则可以支持更先进、对时延敏感的服务，如远程驾驶和通过车云连续体实现的人工智能辅助决策。

4. 车辆移动性如何影响信号强度： 我们评估了车速、环境类型、网络部署模式以及网络切换对信号强度的影响。我们的研究结果表明，有必要提高网络可靠性，并在道路区域扩大 5G 独立组网 (SA) 和未来 6G 接入点的覆盖。这将为在不同车速和网络切换环境下的动态用户增强连接性。

Related Work

The 3GPP [1] has proposed network service requirements for V2X use cases such as vehicle platooning, advanced driving, extended sensors, and remote driving [3] (see Table 2). These service requirements for V2X services are defined based on automation levels, ranging from "lowest" to "highest", and represent the degree to which a vehicle can perform tasks like collision avoidance and cooperative driving based on connectivity. In this study, we categorized the automation levels into low and high by grouping the "lowest", "lower", and "low" levels of automation as "low" and the "high", "higher", and "highest" as "high". This is used to streamline the analysis and compare the test outcomes with the defined requirements. For each category, the minimum limits for E2E latency and throughput are specified, applying to all link types: downlink, uplink, and sidelink.

By meeting the standard service requirements, V2N replacing V2I/V2V is a possibility due to technologies like software-defined networking, network slicing, and network virtualization, which can prioritize vehicle traffic, throughput within the network, and reducing latency [20]. Such a shift could reduce costs associated with deploying and maintaining separate 5.9 GHz-based V2I infrastructure. Hence, the V2N’s ability to cater to V2I or V2I mode-based services must be evaluated through experimental studies, and the V2N limitations must be identified.

Some previous research [25, 26] proposes analytical models for 5G V2X services using simulated environments. There is a lack of experimental evaluations of commercial 5G V2N for V2X, although previous works [12, 23] have experimentally studied the 4/5G V2V/V2I performance in terms of throughput, latency. Similarly, previous works [5, 8] mentioned the usefulness in determining signal strength thresholds for V2I/V2V assisted V2X services, but they have not been defined for V2N. Works on the empirical performances in 5G [13] have focused on network performance in urban and highway scenarios and cross-border environments in [9]. However, there works on V2N capabilities to provision V2X services is lacking, and it is an open research question if there is a possibility of replacing V2I or V2V while maintaining comparable performance. The existing literature has not defined signal strength thresholds for 5G V2N, based on real-world measurements, to support V2X services and automation levels (DoA). Table 1 compares major experimental works on 5G V2X service capabilities and challenges, highlighting the focus in this study.

3GPP [1] 已经为 V2X 的多种用例提出了网络服务要求，例如车辆编队、高级驾驶、扩展传感器和远程驾驶 [3]（见表2）。这些 V2X 服务的服务要求是根据自动化水平定义的，范围从“最低”到“最高”，代表了车辆基于网络连接执行碰撞避免和协同驾驶等任务的能力程度。

在本研究中，我们将自动化等级分为 低级 和 高级，其中“最低”、“较低”和“低”级别归为“低级”，“高”、“较高”和“最高”级别归为“高级”。

此举旨在简化分析，并将测试结果与既定要求进行比较。对于每个类别，标准都规定了端到端时延和吞吐量的最低限值，这些限值适用于所有链路类型：下行链路、上行链路和侧行链路。

由于软件定义网络、网络切片和网络虚拟化等技术能够优先处理车辆流量、保障网络吞吐量并降低时延 [20]，只要满足标准服务要求，V2N 取代 V2I/V2V 就成为一种可能。这种转变可以降低部署和维护独立的、基于 5.9 GHz 频段的 V2I 基础设施所带来的成本。因此，必须通过实验研究来评估 V2N 满足 V2I 或 V2I 模式服务的能力，并识别其局限性。

一些先前的研究 [25, 26] 利用模拟环境为 5G V2X 服务提出了分析模型。尽管已有工作 [12, 23] 在实验上研究了 4/5G V2V/V2I 在吞吐量和时延方面的性能，但目前仍缺乏对商用 5G V2N 用于 V2X 的实验性评估。类似地，先前的工作 [5, 8] 提到了确定信号强度阈值对于 V2I/V2V 辅助的 V2X 服务非常有用，但尚未为 V2N 定义这些阈值。关于 5G 实证性能的研究 [13] 主要关注城市和高速公路场景下的网络性能，而 [9] 则研究了跨境环境。然而，关于 V2N 提供 V2X 服务能力的研究尚付诸阙如，并且在保持可比性能的前提下，V2N 是否有可能取代 V2I 或 V2V 仍是一个开放的研究问题。现有文献尚未基于真实世界的测量数据为 5G V2N 定义信号强度阈值，以支持不同的 V2X 服务和自动化等级 (DoA)。表1比较了关于 5G V2X 服务能力与挑战的主要实验性工作，并突出了本研究的重点。

Experimental Setup and Measurements

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Performance Analysis

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Discussion

We studied the current 5G V2N capability, minimum required signal strength, and limitations to provide V2X network services according to the 3GPP standard requirements. This is needed to determine the network constraints when designing cellular network-assisted vehicular system architectures. As for the existing capabilities, the results showed that meeting the strict latency requirements, <20 ms, and throughput requirements, ≥ 1000 Mbps, for V2X services via 5G V2N remains challenging. Specifically, remote driving, proposed in 3GPP to operate primarily via V2N, is less feasible via the current 5G. However, with 6G, the quality of service for V2X is expected to improve significantly, providing standard performance in latency <1 ms and throughput ≥ 100 Gbps [19]. We defined the RSRP signal strength thresholds required to support low and high-level DoA services based on real-world data. These thresholds can support designing hybrid V2N and V2V connectivity systems.

Limitations: This study conducted cellular network-specific characteristics such as latency, throughput, and RSRP using smartphones instead of in-car antenna. Smartphone-assisted in-car measurements could represent the possible worst-case connectivity conditions, as a smartphone’s performance is limited by lowerquality antennas, shielding from the car’s body, and orientation. In contrast, dedicated V2N hardware typically integrates receiving antennas optimized for dynamic vehicular environments with varying signal strengths and provides better signal reception. Primarily, HTTP-only UL/DL tests were conducted to assess throughput required for accessing edge/cloud servers in V2X-assisted driving. Cross-country tests started from Oulu, Finland (City & Country A), via Kiruna in Sweden (City & Country B), ended in Lødingen, Norway (City & Country C), which may affect global result generalization. 99% of the time, the device connected to the network via 5G NSA. The results represent the NSA performance and may have resulted in higher delays and lesser throughput than the 5G SA connectivity.

Future impact: As 5G SA networks aim to deliver better throughput and E2E latency than NSA, 5G V2N capability evaluation under roadside 5G SA sites is a future focus. Improving handover efficiency and designing 5G V2X architectures that support switching between V2X modes based on signal strength is a future direction. Edge caching, and computing assisted architectures may reduce the latency. Our driving test datasets, which are related to developing V2N-assisted analytical models or systems, is shared on GitHub, eliminating the need for retesting.

我们研究了当前 5G V2N 的能力、所需的最低信号强度及其局限性，以评估其是否能根据 3GPP 标准要求提供 V2X 网络服务。这项研究对于在设计蜂窝网络辅助的车辆系统架构时确定网络约束至关重要。就现有能力而言，结果显示，通过 5G V2N 满足 V2X 服务严格的时延（<20 ms）和吞吐量（≥ 1000 Mbps）要求仍然充满挑战。特别是 3GPP 提议主要通过 V2N 实现的远程驾驶，在当前 5G 网络下可行性较低。然而，随着 6G 的到来，V2X 的服务质量预计将得到显著提升，提供时延 <1 ms 和吞吐量 ≥ 100 Gbps 的标准性能 [19]。我们基于真实世界的数据，定义了支持低级别和高级别自动化服务所需的 RSRP 信号强度阈值。这些阈值可以为设计 V2N 和 V2V 混合连接系统提供支持。

局限性： 本研究使用智能手机而非车载天线来测量蜂窝网络的特定特性，如时延、吞吐量和 RSRP。使用智能手机在车内进行测量可能代表了最差的连接条件，因为智能手机的性能受限于质量较低的天线、车身的屏蔽效应以及设备朝向。相比之下，专用的 V2N 硬件通常集成了为动态车辆环境优化的接收天线，能够适应变化的信号强度并提供更好的信号接收效果。我们主要进行了仅基于 HTTP 的上行/下行链路测试，以评估在 V2X 辅助驾驶中访问边缘/云服务器所需的吞吐量。跨国测试从芬兰奥卢（城市与国家A）开始，途经瑞典基律纳（城市与国家B），最终在挪威勒丁恩（城市与国家C）结束，这可能会影响研究结果的普适性。在 99% 的时间内，设备通过 5G 非独立组网 (NSA) 连接到网络。因此， 研究结果主要代表了 NSA 的性能，这可能导致比 5G 独立组网 (SA) 连接更高的延迟和更低的吞吐量。

未来影响： 由于 5G SA 网络旨在提供比 NSA 更好的吞吐量和端到端时延，未来我们将重点评估路边 5G SA 站点下的 5G V2N 能力。 提高切换效率以及设计能够根据信号强度在不同 V2X 模式间切换的 5G V2X 架构是未来的一个研究方向。边缘缓存和计算辅助的架构可能会降低时延。我们已将本次驾驶测试的数据集在 GitHub 上共享，可用于开发 V2N 辅助的分析模型或系统，从而无需重复进行测试。

Conclusion

We assessed the capability of direct 5G V2N to meet 3GPP network requirements for V2X services through local, and cross-country drive tests. The 5G V2N RSRP for minimum connectivity, low-level DoA, and high-level DoA were -119.5, -112.29, and -102.86 dBm, respectively. We observed that 5G V2N could provide low-level DoA V2X services up to 75% time, potentially serving as an alternative to V2I. Hence, the current 5G V2N can support services that require latency 30 < and < 100 ms and throughput < 500 Mbps. However, 5G V2N struggles to support V2X services that require latency < 20 ms and throughput > 1000 Mbps.

我们通过本地和跨国的驾驶测试，评估了 5G V2N 直连满足 3GPP V2X 服务网络要求的能力。

1. 我们确定了维持最低连接、支持低级别自动化 (DoA) 和高级别 DoA 所需的 RSRP 分别为 -119.5 dBm、-112.29 dBm 和 -102.86 dBm
2. 我们观察到，5G V2N 在高达 75% 的时间内能够提供低级别 DoA 的 V2X 服务，有潜力作为 V2I 的替代方案

本篇论文重点是实践测量. 留意得出的结论即可

因此，当前的 5G V2N 可以支持时延要求在 30 到 100 毫秒之间、吞吐量要求低于 500 Mbps 的服务。然而，5G V2N 难以支持时延要求小于 20 毫秒、吞吐量要求大于 1000 Mbps 的 V2X 服务。