5G helps turn self-driving cars into mobile data centers

Driverless cars (i.e. autonomous driving) are mankind's next decade plan. To realize this dream, a unique combination of technologies is needed to overcome the primary challenges of autonomous driving.

A perfect combination

Autonomous vehicles (AVs) need to process a large amount of information in real time. For example, in order to avoid collisions, detect obstacles and pedestrians, and notify free parking spaces, vehicles need to exchange a large amount of metadata with city infrastructure (such as traffic lights, public safety systems), fog/cloud service providers, and even car manufacturers. According to Intel statistics, the amount of data that such a car needs to process every day will be as high as 3.9TB, which is equivalent to the daily data usage of 2,666 Internet users. Automotive components such as ultrasound, radar, GPS, cameras, and infotainment systems are all factors that contribute to this surge in data.

To ensure secure and scalable data exchange between vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-network (V2N) and vehicle-to-pedestrian (V2P), collectively known as vehicle-to-everything (V2X), a group led by the Institute of Electrical and Electronics Engineers and the U.S. Department of Transportation has developed new standards.

However, V2X standards alone are not enough. In order for vehicles to make complex, autonomous decisions in real time without compromising road safety, V2X systems must be accompanied by a mobile communications ecosystem with speed and data processing capabilities that can match human response. Accidents reported in recent years involving autonomous driving road tests have further emphasized this requirement, leading the Third Generation Partnership Project (3GPP) to develop 5G wireless standards.

How 5G fits into V2X use cases

A common feature of AVs is the ability to continuously perceive the observed environment and thus select driving routes in real time. In bandwidth-constrained radio environments, they must be able to handle high levels of noise and interference as well as highly dynamic configurations of external entities. To support V2X use cases, simply increasing data throughput is not enough. In addition, the network infrastructure must also be able to provide a highly reliable, low-latency network and ensure data security within different communication ranges.

The realization of the following common V2X use cases will ultimately lead the car into a fully connected and automated era:

collaborative awareness (e.g., emergency vehicle alerts);

Collaborative perception (exchanging raw perception data);

Collaborative control (coordinating vehicle routes in lane changes, queuing, intersection control, etc.);

Notify vulnerable road users, i.e. pedestrians, cyclists etc.;

Transportation efficiency (dynamically updated routes, maps, etc.)

To support these use cases, more than one wireless technology may be required, for example, short-range direct communications between devices (V2V, V2I, and V2P) without being dispatched through the network. Device-to-device interfaces using 3GPP Release 12/13 LTE proximity services technology can be used to reliably transmit large amounts of data between neighboring vehicles with ultra-low latency. For vehicle-to-network (V2N) communications, traditional cellular cloud services are required in addition to new 5G wireless technologies.

Connectivity and network performance

Large-scale data and devices are the biggest challenges in the era of autonomous driving. Compared with 4G/LTE, 5G has a 1,000-fold increase in bandwidth per unit area, a 10,000-fold increase in traffic, and a 100-fold increase in the number of connected devices per unit area. 5G small base station technology using millimeter waves has higher spectrum efficiency, which is a major advantage for bandwidth-constrained V2X environments.

reliability

5G promises ultra-low latency of >1ms, which can meet the reliability expectations of mission-critical V2X use cases. Wireless data is relatively easier to intercept and more vulnerable to man-in-the-middle attacks. 5G is expected to improve the security of 5G electronics by including mutual authentication, local secure elements, transport layer security, 99.999% network availability, and firmware over-the-air updates.

Network Slicing

Just like virtual machines on a virtualized hardware platform, 5G's network slicing feature can allow different vendors to provide different categories of automotive services over the same infrastructure. For example, it will allow telecom operators, road operators, and automakers to provide different services to vehicles and their passengers on the same 5G infrastructure.

5G V2X requirements and design considerations

In order to connect vehicles and back-end infrastructure, 5G V2X applications put forward new design requirements for communication systems, so the 5G V2X specification was developed in 3GPP Release 16.

Industry forums such as 3GPP and the 5G Automotive Association have identified use case-specific performance requirements for 5G V2X systems in terms of latency, reliability, and data rate. 3GPP has identified the following five categories of requirements for 5G V2X:

General purpose: applicable to interconnection and communication requirements of all V2X scenarios

Vehicle queuing: Vehicles moving slowly with very small spacing

Advanced Driving: Semi- or Fully Automated Driving

Extended sensors: Information exchange between all V2X-enabled devices and network elements

Remote driving: remote control by a human driver (e.g. in hazardous environments)

It is important to note that the requirements for 5G V2X systems depend on the use case scenario (Figure 1). Routine lane change operations have much less latency and reliability requirements than cooperative maneuvers in emergency situations.

Figure 1: This diagram shows the V2X requirements for 5G latency and data rates as defined in the 3GPP guidelines and fine-tuned based on input from automotive OEMs (Source: Use Cases, Requirements, and Design Considerations for 5G/V2X on arxiv.org)

in conclusion

AVs are essentially mobile data centers; they rely heavily on edge computing capabilities. It would take about 230 days to transmit a week’s worth of data from an autonomous vehicle via an advanced Wi-Fi connection. Therefore, disruptive innovations in product and application-specific integrated circuit processing technologies for new radio and antenna architectures are critical to supporting 5G V2X.