In-Vehicle Connectivity: Dealing with the “Elephant in the Car”

Often overlooked in the push toward self-driving vehicles are requirements for lower total system cost, reduced cable length/weight, and the ability to meet EMC specs.


By Micha Risling, SVP Marketing & Business Development, Head of Valens’ Automotive Business Unit

For a fully autonomous vehicle to drive safely, it must depend on a slew of cameras, sensors, and radar to detect traffic lights, read road signs, keep track of other vehicles, and look out for pedestrians and other obstacles in the path of the vehicle. At the same time, driven by demand for seamless phone-to-car infotainment via applications such as CarPlay and Android Auto, larger displays and user-friendly control systems are enabling a more enjoyable ride along with superior phone, music, messaging, and navigation experiences.

Figure 1: Consumer demand for in-car functionality calls for connecting different applications over the same link. 

Every time a new feature or device is added to a vehicle, however, so, too, are other elements such as additional cables, semiconductors and connectors. These provide the bandwidth required to transmit the data from each device and application to the car’s central electronic control unit (ECU) and between the car’s different processors. With each of these essential additions, the complexity, weight, and cost of the car goes up.

That’s a problem. So much of a problem in terms of weight and bulk that the wiring and cabling has become the modern “elephant in the car.” To achieve the levels of connectivity and autonomy that automakers are striving for, more links, more semiconductors, and more cables are needed to efficiently and quickly relay the increasing amount of data and bandwidth. Before long, car manufacturers will be unable to add any more without degrading performance and exploding cost budgets.

Cars are already bursting at the seams with cables and devices, and connectivity still isn’t at a desirable level, let alone enabling full connectivity and autonomy. In fact, wiring and cables represent a considerable weight component in vehicles, oftentimes representing the third heaviest and costliest component after the chassis and the engine. And yet, even with additional cabling, an increase in the throughput of data transferred hasn’t been achieved simply because the underlying technologies being used can’t deliver it.

Under the Hood: Getting Down to Business

The problem as we see it (and the reason Valens Automotive was established), is that today’s vehicle infrastructure relies heavily on yesterday’s technology, built to support the transmission of data between just a few electronic sensors, usually at low bandwidth. But as cars become data-centers-on-wheels, it’s critical to simplify and optimize the wire harness to create a suitable environment for the connected and autonomous car.

Research from Strategy Analytics indicates that by 2024, vehicles will have twice as many semiconductors as today to support new systems and applications. This will amount to more than 16 sensors per car, including numerous cameras, radars, LiDARs, displays, and more. They will all need to be connected to each other (cameras to displays, for example) and to the many microcontroller units (MCUs) and electronic control units (ECUs) in the vehicle.

Figure 2: Data from LiDAR, cameras, and other sensors must be routed to ADAS ECUs and other processors.

The key questions are as follows:

  • How do we manage to transfer data from point A to point B in a safe manner, at a high data rate, and without adding delay that could be dangerous in a car?
  • How do we ensure that the quality of camera views is at the highest level in order to deliver the information necessary to prevent collisions and accidents?
  • How do we manage the influx of external data coming from GPS, traffic and speed systems, etc.?

To address these questions, we must determine the best options for in-vehicle connectivity, both in terms of cable infrastructure and transmission technology.

Current cable options include:

  • Copper wires: These wires are the most obvious choice for connectivity, given the relative low cost and ease of use. They are twisted in pairs to minimize electromagnetic interference (EMI). There are two main types:
    • Shielded twisted pair (STP): Each pair is shielded to further protect data transmission from EMI, particularly when higher rates or distances are involved.
    • Unshielded twisted pair (UTP): As the name implies, these cables don’t contain extra shielding, and are more prone to interference, which can affect performance. UTP is more widely used since they cost less, are more manageable, and don’t have grounding issues. STP is more expensive, heavier, and increases complexity because it must be grounded.  However, without a technology that can handle high EMI/EMC variables, UTP becomes a difficult option, and that explains why several existing technologies demand STP or even coax. This is one of the existing challenges with Ethernet technology and puts OEMs in the difficult position of deciding whether bandwidth/connectivity is more important than overall system cost and efficiency.
  • Coaxial cables: Coax cables are used when higher bandwidth is needed. It’s a robust, shielded option, which makes it resilient to EMC, and is used in today’s vehicles. However, it’s less flexible than UTP. A significantly bulky option, coax adds considerable weight to the car system.
  • Optical fibers: Although it seems like an obvious option since it can support very high bandwidth and is immune to EMI/EMC, glass optical fiber isn’t yet an option widely adopted in vehicles due to high cost. Optical fibers are also limited in terms of bend radius, and aren’t as resilient to the vibrations found in the vehicle environment. Plastic optical fiber is a more cost-effective option, and more resilient, but it supports lower bandwidth and shorter distances, and still requires expensive optical transceivers. Both glass and plastic optical fibers don’t enable the transmission of power.
  • Wireless: Wireless isn’t yet an optimal choice for in-vehicle connectivity because it lacks the reliability necessary to guarantee safety in ADAS. Wireless transmission often leads to significant latency in the transmission of data, further increasing the risk for drivers and passengers. It also depends on the overall cell tower and network infrastructure, and would severely limit connected-car capabilities in areas where the infrastructure doesn’t match that of urban centers.

Existing In-Vehicle Connectivity Solutions

For decades, cars have been outfitted with connectivity technologies that enable the transmission of data within vehicles. Many of these—such as MOST and CAN—focus on low-bandwidth transmission of data, and still play a vital role in today’s cars simply because not every device and system needs high-speed connectivity.

The CAN bus operates at speeds of less than 1 Mb/s, and message lengths (CAN frames) are typically 50 to 100 bits. MOST is a legacy audio bus technology that has gone through three evolutions: MOST 25, MOST 50, and MOST 150; the number indicates the bandwidth, e.g., MOST 150, introduced in 2007, can carry audio or video data at speeds of 150 Mb/s.

Other in-vehicle connectivity technologies, such as Ethernet and SerDes (serializer/deserializer) can also deliver higher bandwidth. When introduced in 2008, automotive Ethernet brought many advantages, such as a unified diagnostics interface and fast software download, with greatly improved data-transmission rates.  Most cars today are equipped with 100Base-T1, enabling 100-Mb/s, full duplex, over the lightweight UTP wire harness. The near future is looking at 1 Gb/s (1000Base-T1). However, that won’t even be enough to support the needs of all the cameras, sensors, LiDARs, and infotainment and telematics units, as well as the challenges of working over UTP.

SerDes technology provides higher bandwidth—from 1.5 to 3 Gb/s, or above, depending on how many pairs are used. However, most SerDes technologies today can’t be transmitted over UTPs, and rely either on coax or shielded twisted pairs, reducing flexibility and increasing weight and space taken by cables, as mentioned earlier.

Introducing HDBaseT Automotive

Given the current and future demands for additional in-vehicle connectivity from applications and bandwidth, and the challenges of weight and space, the solution is to address OEM needs with a data-transmission technology that delivers the performance necessary for a superior driving experience. HDBaseT Automotive is a technology solution designed to deliver the bandwidth needed to truly enable the connected and autonomous car, and it does so with the simplest infrastructure available—unshielded twisted-pair cables—keeping cost and weight down.

HDBaseT, a chipset technology developed by Valens, was initially deployed to address the challenges of multimedia and data transmission in the audiovisual and consumer electronics market. HDBaseT quickly became a standard in the industry, as it enables the transmission of audio and video, Ethernet, USB, controls, and even power, over a single category cable for up to 100 m/328 ft.

As the automotive industry started increasing the levels of in-vehicle connectivity, Valens realized that the same challenges it addressed in the consumer audiovisual market were present in the automotive industry:  increased bandwidth, too many cables, complexity, distance, latency, and performance, just to name a few.  With some minor modifications to comply with automotive industry requirements, Valens introduced HDBaseT Automotive.

HDBaseT Automotive semiconductors tunnel high-bandwidth data and flexible architectures and connectivity—at significant cost savings—over UTP cables.

Benefits of using HDBaseT Automotive include:

  • Bandwidth: HDBaseT Automotive transmits multiGig data, with near-zero latency, delivering the bandwidth necessary to enable several connected devices and applications in vehicles.
  • EMC: HDBaseT Automotive is able to meet the stringent EMC/EMI requirements of the automotive industry, neutralizing interference caused by adjacent systems and minimizing its own emissions thanks to proprietary mechanisms that also guarantee redundancy for greater reliability. The technology has been tested by several OEMs and Tier-1s with positive results.
  • Reduction in the number of cables and connectors at a system level: HDBaseT Automotive enables daisy-chaining topologies and the simultaneous streaming of video and data links to different devices. And, unlike automotive Ethernet, reduces the number and length of required cables, connectors, inline connectors, and chipsets.
  • Tunneling of interfaces for longer distances than possible until now: HDBaseT Automotive is the first and only technology on the market that can transmit certain interfaces, such as USB 3.1 and PCIe, natively over a 15-m/50-ft. UTP. PCIe extension is a particularly attractive proposition, as an increased number of ECUs are necessary to handle the data within cars. By extending PCIe, HDBaseT Automotive provides flexibility on the location of these ECUs, and eliminates the need for extra memory devices (solid-state disks, or SSDs).


Figure 3

Figure 3: HDBaseT uses unshielded twisted-pair cables to minimize cost and weight.

Ultimately, HDBaseT Automotive leads to a lower overall system cost, reduces the number and weight of cables, and eliminates extra devices while enabling higher bandwidth and applications over a leaner infrastructure.

Secure Transmission is Critical

Security is a major concern with connectivity, and the in-vehicle network environment offers hackers more than personal data. HDBaseT Automotive is an inherently secure technology, with embedded connectivity protocols to address cybersecurity risks. This is where standardization plays a role. In fact, the HDBaseT Alliance, originally founded by Valens together with LG Electronics, Samsung Electronics, and Sony Pictures—and now a 200-member strong organization—has enabled the company to further the goal of standardizing and advancing a secure HDBaseT technology.

Within the alliance is the Cybersecurity Work Group, which includes global cybersecurity leaders Check Point and Argus Cyber Security (recently acquired by Continental) to contribute their best practices for secure connectivity. A key element in connectivity is looking at all factors involved: bandwidth, architecture and topology, convergence and consolidation of applications and computing power, EMC, and cybersecurity to fulfill the true promises of connectivity.


Valens is at the forefront of the in-vehicle connectivity revolution, currently working with several OEMs and Tier 1 and Tier 2 suppliers, discussing the specific challenges and needs of each manufacturer, and determining how HDBaseT Automotive can be deployed to address vehicle architecture issues. For example, in November 2016, Valens and Daimler announced their collaboration to bring HDBaseT Automotive into cars in the near future.

HDBaseT Automotive is directly addressing the main challenge facing OEMs and Tier 1s in reaching the full potential of in-vehicle connectivity: inadequate vehicle infrastructure.  HDBaseT Automotive allows key stakeholders in the automotive industry to leverage a simple UTP cable to enable the full range of connectivity that will drive our future as device and bandwidth usage ramps up.

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