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A Vision of C-V2X: Technologies, Field Testing and Challenges with Chinese Development

Shenzhi Chen, Jinling Hu, Yan Shi, Li Zhao, Wen Li

arXiv:2002.08736v1eess.SPcs.NI

TL;DR

Autonomous driving and intelligent transportation require communication that addresses the limited perception and computation of single-vehicle systems. This paper synthesizes C-V2X’s evolution, technologies, standards, testing, and Chinese development, concluding that C-V2X with 5G technologies supports connected vehicle intelligence while facing several technical challenges.

  • Problem

    Single-vehicle sensing and computation have limited capabilities, motivating communication support for autonomous driving and intelligent transportation applications.

  • Method

    The paper presents a vision of C-V2X by synthesizing its evolution, requirements, architecture, key technologies, standards, global deployment, testing, and Chinese development.

  • Results

    The paper envisions three application phases and analyzes challenges involving MEC integration, channel modeling, high-accuracy positioning, and radar-communication integration.

  • Takeaways & Limitations

    C-V2X with 5G technologies is presented as supporting evolution from single-vehicle intelligence to connected vehicle intelligence for autonomous driving and intelligent transportation.

  • Takeaways & Limitations

    5G network high-precision positioning lacks clear 3GPP standards, while RTK is unsuitable for large-scale applications because of its high price.

Abstract

from arXiv · show

C-V2X (Cellular Vehicle-to-Everything) is the important enabling technology for autonomous driving and intelligent transportation systems. It evolves from LTE (Long Term Evolution)-V2X to NR (New Radio)-V2X, which will coexist and be complementary with each other to provide low latency, high reliability, and high throughput communications for various C-V2X applications. In this article, a vision of C-V2X is presented. The requirements of the basic road safety and advanced applications, the architecture, the key technologies, and the standards of C-V2X are introduced, highlighting the technical evolution path from LTE-V2X to NR-V2X. Especially, based on the continual and active promotion of C-V2X research, field testing and development in China, the related works and progresses are also presented. Lastly, the trends of C-V2X applications with technical challenges are envisioned.

I. INTRODUCTION · II. C-V2X: FROM LTE-V2X TO NR-V2X

The paper presents C-V2X as a cellular-based enabler of low-latency, high-reliability vehicular communications for autonomous driving and intelligent transportation. It traces the evolution from LTE-V2X to complementary NR-V2X and outlines the article’s coverage of technologies, standards, Chinese development, testing, applications, and challenges.

  • I. INTRODUCTION: C-V2X leverages cellular systems to support low-latency, high-reliability V2V, V2P, V2I, and V2N communications.It is presented as communication among vehicles, pedestrians, infrastructure, and networks.
  • II. C-V2X: FROM LTE-V2X TO NR-V2X: C-V2X evolves with cellular systems from 4G LTE to 5G, progressing from LTE-V2X to NR-V2X.The evolution is described as a technology transition accompanying cellular-system development.
  • I. INTRODUCTION: LTE-V technology was proposed in May 2013 by CATT/Datang based on TD-LTE, with LTE-V-Direct and LTE-V-Cell modes.LTE-V-Direct supports direct V2V/V2I communications and basic road safety applications, while LTE-V-Cell uses centralized control and forwarding through an eNB.
  • I. INTRODUCTION: C-V2X is identified as an important enabling technology for autonomous driving and intelligent transportation systems.The paper frames C-V2X as central to these transportation objectives.
  • I. INTRODUCTION: China has actively promoted C-V2X standardization, research and development, testing, and industrial practice through cooperation with automobile and transportation industries.The passage specifically names CATT/Datang and Huawei among the promoting Chinese companies.
  • I. INTRODUCTION: The article presents a C-V2X vision covering technologies, standards, global development, Chinese promotion, technical trends, challenges, and conclusions.Its sections separately address global C-V2X technologies and standards, Chinese development, technical trends, challenges, and the conclusion.
  • II. C-V2X: FROM LTE-V2X TO NR-V2X: LTE-V2X is the initial C-V2X version, primarily based on LTE and sufficient for basic road safety services through status-information exchange.Exchanged information includes position, heading, and speed among neighboring vehicles, pedestrians, and infrastructure.
  • II. C-V2X: FROM LTE-V2X TO NR-V2X: NR-V2X complements rather than replaces LTE-V2X, supporting current and future applications through enhanced radio-layer features and network architecture.Active communications provide an enhanced perception horizon across varied use cases, scenarios, and applications.

A. Technologies … 3) Key Technologies of C-V2X  The physical layer structure design

The paper presents C-V2X as an evolution from LTE-V2X to complementary NR-V2X, combining cellular architecture, sidelink resource management, and physical-layer enhancements to support increasingly demanding V2X services. It covers basic road safety, 25 advanced use cases, and technical mechanisms targeting low latency, reliability, capacity, coverage, and flexible communication modes.

  • A. Technologies: C-V2X evolves from LTE-V2X to NR-V2X, with both technologies intended to coexist and complement one another.This evolution is framed around supporting diverse V2X applications through progressively enhanced communication capabilities.
  • 1) The requirements of the basic road safety and the advanced V2X services: 3GPP Rel-14/Rel-15 sufficiently supports basic road safety warnings, while 25 advanced use cases span platooning, extended sensors, advanced driving, and remote driving.The advanced services reflect more stringent requirements and broader functional capabilities than basic warning-message broadcasting.
  • 2) The centralized/ distributed architecture and communications: LTE-V2X reuses LTE-D2D for direct sidelink communication through centralized Mode 3 and decentralized Mode 4 scheduling.New V2X Control Functions are added to the legacy LTE core network for authorization and provisioning.
  • 2) The centralized/ distributed architecture and communications: Unlike IEEE 802.11p’s contention-based CSMA/CA, LTE-V2X uses sensing-assisted SPS and counter-based reselection to manage periodic safety-service transmissions and reduce persistent collisions.Resource selection uses sensing results and service priorities to estimate resource occupation and configure sensing thresholds.
  • 3) Key Technologies of C-V2X  The physical layer structure design: At 140 km/h and 5.9 GHz, LTE-V2X increases DMRS density from two to four time-domain columns to support channel estimation and synchronization tracking under high Doppler.This physical-layer adjustment addresses the combined effects of high vehicle speed and high center frequency.
  • 3) Key Technologies of C-V2X  The physical layer structure design: LTE-V2X improves reliability through turbo-code, HARQ, and SC-FDM coding gains, while synchronous FDM resource allocation improves spectral efficiency and system capacity.Geographical zoning can also allocate resources through eNBs in centralized mode or UEs in distributed mode to mitigate Near-Far collisions and provide spatial division multiplexing gain.
  • 3) Key Technologies of C-V2X  The physical layer structure design: LTE-V2X can support eV2X services, some platooning, and limited automated driving, whereas complementary NR-V2X targets services requiring extreme low latency, high reliability, capacity, coverage, and extensibility.NR-V2X proposals include flexible sidelink signals, channels, bandwidth parts, and resource pools supporting unicast and groupcast with feedback in addition to broadcast.
  • 3) Key Technologies of C-V2X  The physical layer structure design: Harmonization among IEEE 802.11p, LTE-V2X, and NR-V2X is presented as a way to maintain C-V2X advantages while enabling the evolution from LTE-V2X to NR-V2X.The comparison is summarized through the technologies’ key differences in the paper’s Table II.

B. Standards

C-V2X standards span radio and application layers, with 3GPP driving the cellular radio evolution from completed LTE-V2X standards toward ongoing NR-V2X standardization. International and regional organizations complement this work through interoperability, security, frequency, architecture, and application standards.

  • Standards organization: C-V2X standards comprise radio-layer specifications led by 3GPP and higher-layer standards developed by countries and regions for differentiated application requirements.3GPP focuses on the radio layer, while national and regional bodies address higher-layer needs.
  • 3GPP: 3GPP C-V2X standardization is organized into three phases, with LTE-V2X development completed and NR-V2X research and development continuing.The article identifies 3GPP as the driver of C-V2X standardization alongside 4G/5G cellular evolution.
  • 3GPP: Rel-14, completed in March 2017, introduced standards for V2V and additional infrastructure-enabled V2X services, including basic safety through sidelink status exchange.Rel-15, completed in June 2018, extended LTE-V2X in a complementary manner to Rel-14.
  • 3GPP: NR-V2X is designed for advanced services requiring lower latency, higher reliability, higher throughput, greater capacity, larger coverage, and future-service extendibility while maintaining backward compatibility with Rel-14 and Rel-15.NR-V2X standardization was launched in June 2018.
  • Other standards bodies: ITU, ISO, ETSI, and SAE address complementary aspects including ITS frequency harmonization, security, LTE-V2X candidate standardization, C-V2X protocol-stack availability, and interoperability requirements.SAE J3161 adapts SAE J2945.1 to LTE-V2X and defines profiles, functional parameters, and performance requirements; the related work was completed in 2018.

C. Global Development

Global C-V2X development is advancing through cross-industry coordination, international pilot construction, field testing, and interoperability demonstrations. Activities in the United States, Europe, Japan, and South Korea are accelerating intelligent connected vehicle industrialization.

  • Global organizations: 5GAA, founded in September 2016, supports C-V2X for mobility and transportation services and includes more than 110 automotive, telecommunications, and IT companies.Its Day-one function and system profiles were completed in 2018.
  • Global organizations: NGMN established a V2X task force in July 2016 to connect mobile network operators with the automotive industry and accelerate LTE-V2X time-to-market through shared trial results.The task force also promoted operator views on LTE-based V2X and DSRC.
  • International field development: The United States, Europe, Japan, and South Korea have conducted C-V2X pilot-area construction, field tests, and technical capability verification in actual operations.These activities are further accelerating the industrialization of intelligent connected vehicles.
  • International field development: The first C-V2X regional trial began in San Diego in October 2017, where multi-OEM demonstrations were implemented and interoperability was verified.The trial involved Ford, Nokia, AT&T, and Qualcomm.
  • International field development: A 2018 Japanese trial summarized PC5 direct-communication and Uu LTE network performance findings to demonstrate the benefits of direct and network-based C-V2X communications.Participants included NTT Docomo, Nissan, Continental, Ericsson, and Qualcomm.

III. C-V2X IN CHINA

China has achieved fruitful progress in C-V2X through an all-round national layout and promotion. This effort spans policy planning, standards and technology research and development, industry implementation, and vehicle-networking field trials.

  • China has promoted C-V2X through policy planning.
  • China has advanced C-V2X standards and technology research and development.
  • China has pursued industry implementation and vehicle-networking field trials for C-V2X.

A. Policies

China advanced C-V2X and intelligent connected vehicle development through coordinated industry governance, dedicated LTE-V2X spectrum planning, field-test approvals, and a staged industrial promotion action plan.

  • Governance: In September 2017, China established the Special Committee of ICV Industry to coordinate policies, major development problems, implementation supervision, and industrial promotion.The committee was responsible for top-level development planning and policy organization.
  • Spectrum and field testing: In October 2018, MIIT dedicated the 5905 to 5925 MHz band to LTE-V2X PC5 and approved LTE-V2X deployment and operation licenses for field tests in Hainan Province and Tianjin.The approvals supported on-the-ground field testing.
  • Industrial roadmap: In December 2018, MIIT published an intelligent and connected vehicle industry promotion action plan targeting high-quality development through two stages.The first stage targeted 2020 breakthroughs in cross-industry vehicular-networking integration and LTE-V2X deployment at a certain scale in specific scenarios.

B. Standards · C. Interoperability Testing · D. China ICV Development

China’s ICV standardization established a four-part architecture and layered LTE-V2X standards, while interoperability trials and pilot-area deployments advanced cross-industry C-V2X testing and application development. These efforts extended to security demonstrations, national projects, and planned 5G/C-V2X use at the 2022 Beijing Winter Olympics.

  • B. Standards: MIIT released the ICV standard-architecture guidelines in four parts in December 2017, with the standards-system structure presented in Fig. 2.
  • B. Standards: Chinese standards organizations are layering automotive, transportation, communications, and traffic-management requirements into an ICV standards stack.
  • B. Standards: China completed core LTE-V2X standards across the access, network, security, facility, and application layers to support diverse V2X applications.
  • C. Interoperability Testing: A CAICV, IMT-2020 PG C-V2X task force, and SIAC trial tested cross-chipset/module, cross-TBOX, and cross-OEM LTE-V2X interoperability using Chinese application standards and LTE-V2X Mode 4.
  • C. Interoperability Testing: Security verification and demonstration of LTE-V2X communications was planned for October 2019, building on Chinese security standards and the triple-cross interoperability trial.
  • D. China ICV Development: MIIT and the Ministry of Transportation worked with local governments to establish C-V2X pilot areas, including provinces conducting cross-industry intelligent-vehicle and transportation demonstrations.
  • D. China ICV Development: National projects promoted ICV killer applications and industrialization, while the Tech-driven Winter Olympics program planned extensive 5G and C-V2X adoption for Beijing’s 2022 Winter Olympics.

E. Industrial Practice

China has developed a complete C-V2X industrial chain spanning communication modules and chipsets, vehicle-road terminals, and applications. Field deployment in Xiamen’s intelligent bus system has verified multiple cooperative applications, while 3000 kilometers of first-stage testing confirmed LTE-V2X reliability and bus stability.

  • Industrial ecosystem: China’s C-V2X ecosystem has formed a complete industrial chain covering communication modules and chipsets, OBU and RSU terminals, and safety and efficiency applications.Commercial communication products include DMD31, Balong 765, and Qualcomm 9150, while companies such as Neusoft, Nebula, Transinfo, and Quectel launched terminals.
  • Intelligent bus system: In Xiamen’s intelligent bus system, C-V2X devices are deployed on BRT buses and RSUs, with 5G NR coverage across the entire BRT line.The system architecture integrates the deployed C-V2X devices with the BRT infrastructure.
  • Intelligent bus system: MEC-enabled V2V and V2I communications support cooperative perception with low latency, high reliability, and high throughput.These capabilities are provided within the intelligent bus system’s 5G NR-covered BRT environment.
  • Verified applications: The intelligent bus system verified precise parking, NLOS collision avoidance, NLOS intersection information exchange, traffic signal adjustment, prioritized public buses, and optimal driving strategies.These applications are described as vehicle-road cooperative applications supported by the system.
  • Field verification: 3000 kilometers of first-stage verification confirmed LTE-V2X reliability and the stability of buses equipped with LTE-V2X devices.The passage also reports a possible fuel-consumption reduction, but its value is truncated in the supplied text.

IV. THE TECHNICAL TRENDS AND CHALLENGES OF C-V2X APPLICATIONS

C-V2X enables a transition from single-vehicle intelligence to connected intelligence through information exchange, environment perception, and cooperative decision and control. Its envisioned applications progress from improving traffic efficiency and road safety to autonomous driving of commercial and passenger vehicles, while requiring technical challenges to be addressed.

  • Technical motivation: C-V2X enables the shift from single-vehicle intelligence to connected intelligence by supporting information exchange and environment perception.Single-vehicle sensing, computing, and communication suffer from limited perception capability, mainly because sensing is often restricted to line-of-sight range.
  • Technical motivation: Together with MEC and 5G network technologies, C-V2X supports low-latency, highly reliable delivery of computation tasks, decisions, and control instructions for cooperative decision and control.V2V, V2I, V2P, and V2N communications enable cooperative perception between vehicles and infrastructure, pedestrians, and networks.
  • Phase 1: Improving traffic efficiency and road safety: Phase 1 improves traffic efficiency and road safety through Vehicle-Vehicle and Vehicle-Road cooperative perception capabilities.This phase focuses on cooperative perception rather than autonomous driving control.
  • Phase 2: Autonomous driving of commercial vehicles: Phase 2 targets low-speed autonomous driving for commercial vehicles in enclosed areas using MEC-enabled cooperative decision and control.Examples include industrial parks, harbors, wharfs, and mining areas, with heavy-duty trucks identified as an example.
  • Phase 3: Autonomous driving of passenger vehicles: Phase 3 targets high-speed autonomous driving for passenger vehicles after widespread deployment of C-V2X and MEC.This phase provides cooperative decision and control capabilities for high-speed passenger vehicles.

A. Integration with MEC · B. Channel Modeling · C. 5G enhancement based high-accuracy positioning

The section examines C-V2X’s integration with MEC, the distinctive and challenging vehicular channel environment, and 5G-enabled high-accuracy positioning. It highlights resource-convergence challenges, specialized channel-modeling requirements, and unresolved positioning-standardization and scalability issues.

  • A. Integration with MEC: MEC places computation and storage resources at the network edge, augmenting mobile terminals while supporting low latency, high reliability, transmission efficiency, and deployment flexibility.
  • A. Integration with MEC: C-V2X–MEC integration provides communication-computing-storage convergence for traffic control, congestion analysis, HD map loading, path planning, and heterogeneous data fusion.These applications require computing-intensive or data-intensive tasks including big data analysis, data mining, and deep learning.
  • A. Integration with MEC: Integration challenges include dynamic resource deployment and joint scheduling, computation offloading, communication handover, computation migration, and interoperability and compliance.The passage identifies ETSI, 3GPP, and 5GAA as key standardization organizations.
  • B. Channel Modeling: Vehicular channel modeling underpins communication-system design and performance evaluation, but V2V propagation differs significantly from cellular communication channels.
  • B. Channel Modeling: High-mobility transmitters and receivers plus moving scatterers produce large, time-varying Doppler shifts, deep fading, and space-time-frequency non-stationarity.Deep fading includes “worse than Rayleigh” fading in a significant percentage of cases.
  • B. Channel Modeling: Channel-modeling challenges span hybrid statistical-geometric models, mmWave measurements, non-stationary characterization, multipath tracking and clustering, and machine-learning-based channel prediction.
  • C. 5G enhancement based high-accuracy positioning: High-accuracy positioning is essential for driving decisions because a 100 km/h vehicle travels 28 meters per second, while 5G multi-antenna technology improves positioning capability.5G networks can also update high-definition maps quickly.
  • C. 5G enhancement based high-accuracy positioning: 5G high-precision positioning lacks clear 3GPP standards, RTK is costly for large-scale deployment, and feasible relative-positioning technology remains insufficient.Relative positioning could reduce vehicle-positioning costs using RSUs or roadside 5G eNBs.

D. The integration of radar and C-V2X communications · V. CONCLUSION

The paper presents radar–C-V2X integration as a promising but challenging approach for combining vehicular data exchange with target detection. It concludes that C-V2X evolves from LTE-V2X for basic road safety toward coexistence with NR-V2X for advanced autonomous-driving and intelligent-transportation applications.

  • D. The integration of radar and C-V2X communications: Radar–communication integration and co-design is promising because vehicular systems require both data exchange and target detection at millimeter-wave frequencies.The paper notes that automotive radars and future C-V2X systems operate in the millimeter-wave band.
  • D. The integration of radar and C-V2X communications: Sharing and jointly processing detection results from different radars can improve detection accuracy and enable comprehensive automotive environment sensing.C-V2X communication capability supports this collaborative sensing process.
  • D. The integration of radar and C-V2X communications: Integration requires joint waveform design, mmWave signal separation, communication-waveform-based radar echo orientation, and extremely high-accuracy time synchronization.These requirements arise because C-V2X communications and radar differ in modulation, bandwidth, and circuit requirements.
  • V. CONCLUSION: C-V2X provides low-latency, high-reliability, and high-throughput communications by leveraging and enhancing current cellular systems.Its evolution proceeds from LTE-V2X to NR-V2X.
  • V. CONCLUSION: LTE-V2X supports information exchange for basic road-safety applications, while NR-V2X coexists with LTE-V2X to support advanced autonomous-driving and intelligent-transportation applications.The two technologies are presented as complementary stages in the C-V2X evolution path.
  • V. CONCLUSION: The paper presents a C-V2X vision covering application requirements, centralized/distributed architecture, key technologies, standards research, global deployment, field testing, and technical verifications.The organization follows the evolution path from LTE-V2X to NR-V2X and addresses both road-safety and advanced applications.
  • V. CONCLUSION: Together with 5G technologies such as MEC, C-V2X is envisioned to advance intelligence from individual vehicles to connected vehicles, supporting autonomous driving and intelligent transportation systems.The paper envisions three application phases: improving traffic efficiency and road safety, autonomous driving for commercial vehicles, and autonomous driving for passenger vehicles.
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