DSRC vs C-V2X: Comparing the Connected Vehicles Technologies

Connected vehicles are a guaranteed part of our future, but the technology they will use is anything but. Two distinct technologies are fighting it out for dominance in the sector: DSRC and C-V2X. Both allow vehicles to communicate with each other (V2V) and to surrounding infrastructure (V2I) securely yet are very different in some key aspects. Most notably, a DSRC device using a WAVE wireless standard cannot communicate with a C-V2X device using Long-Term Evolution (LTE), and vice versa. This lack of interoperability has left the market fragmented with companies choosing sides as the technologies battle it out in Smart Cities across the globe.

Whichever technology you utilise, GTT Wireless can support you with our range of indoor and outdoor antenna and our IP67 outdoor weatherproof electronics enclosure.

What do DSRC and C-2VX have in common?

Before we examine the differences between the technologies and their possible strengths over each other, let’s look at the similarities between the two. No connection is maintained between devices with either DSRC or C-V2X, and both share the same information; each device is simply broadcasting status elements such as location, acceleration, and speed while listening to other nearby devices at the same time. Digital signatures are utilised in both technologies to guarantee security and ensure the validity of transmissions. Both C-V2X and DSRC communicate directly using the 5.9Ghz band and even use the same message sets, SAE J2945 and J2735.

DSRC’s Strengths over C-V2X.

A crucial advantage DSRC has over C-V2X is time. Dedicated Short-Range Communications (DSRC) entered production in some Toyota car models, specifically in Japan, in 2015, before Cadillac followed suit in 2017. Europe’s most popular car, the Volkswagen Golf began utilising the technology in its eighth-generation model back in 2019; this mass market application being a huge sign of confidence in DSRC’s current and future potential. By comparison, C-V2X has only had small initial deployments starting in 2021. DSRC is the more proven technology, already fully designed for the automotive industry and ready for application without having to rely on existing infrastructure.

The Wi-Fi wireless standard DSRC uses, with its OFDOM modulation, has a communication range of upwards of 1km. Because it is purposefully designed for vehicular applications, DSRC works effectively at speeds up to 500 km/h, making it perfect for vehicles other than just cars, such as trains. Of course, there are drawbacks inherent to wireless communication, such as limited channels, particularly in metropolitan areas, but also the volume of data needing to be transmitted. However, DSRC’s messages are of very low data volume, whereas an autonomous car using C-V2X will use an estimated 4000GB of data per day.

DSRC outperforms C-V2X in a number of fields. Its use of WLAN is perfect because of its low latency. DSRC has an average transmission time of only 0.4mS compared to 1mS for C-V2X. In terms of time synchronisation, DSRC is loose asynchronous while C-V2X has very tight synchronous requirements. DSRC’s symbol duration is 8uS fast channel tracking while C-V2X’s is 71uS. Coding gain for C-V2X uses turbo code and HARQ compared to DSRC’s convolution code.

C-V2X’s Strengths over DSRC.

C-V2X’s use of Long-Term Evolution (LTE) is a potential game changer for the connected vehicles industry. Because LTE chip technology is found in almost all cellular devices, C-V2X can use existing cellular infrastructure, both on the roadside and increasingly found in vehicles, which could reduce the amount needed to be installed and maintained. Utilising already well-established LTE technology can create a comprehensive network, enabling high speed communication in high-density locations, using technology people are already well accustomed to.

LTE has a clear upgrade path with 5G networks increasingly becoming available for use, making C-V2X future-facing and able to take advantage of new high speeds. In 2021, C-V2X was named the new standard for connected vehicles technology over DSRC in the United States by the FCC in a controversial ruling. The Intelligent Transport System (ITM), of which V2X is a part, was limited to using only the upper 30 Megahertz of the 5.9Ghz communication band, making C-V2X the go-to technology for a huge market.

C-V2X is still in the early days of application but tests indicate that it could achieve 20-30% greater range than its DSRC rival, and even perform better when faced with obstructions too. C-V2X, with its SC-FDM modulation, is also able to achieve concurrent transmissions while DSRC cannot. The cellular technology overcomes network collisions using retransmission, usually activated at high speed, which can also increase its communication range.

Whichever Connected Vehicles technology you use, GTT Wireless can support you.

Products from GTT Wireless can be employed in both C-V2X and DSRC connected vehicles technology applications, and a variety of Internet of Things (IoT) operations. GTT Wireless stock a large range of outdoor antenna designed to perform consistently and withstand extreme temperatures with robust IP67/NEMA6 waterproof and UV-resistant designs. Featuring an industry standard N Plug connector, our LTE and DSRC antenna are perfect for your mission critical project and our easy-to-use electronics enclosure designer allows you to quickly build a waterproof enclosure for your electronics.