Wireless coexistence and interference: The connected car conundrum
Automotive electronics manufacturers have to be good jugglers to keep the connected car revolution moving forward despite the ever-increasing complexity and costs of implementing applications based on vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), vehicle-to-pedestrian (V2P), vehicle-to-network (V2N), vehicle-to-grid (V2G), vehicle-to-home (V2H), and eventually vehicle-to-everything (V2X) communications.
The world is converging in many ways and boundaries between technology applications are disappearing. A great example of technology convergence is the automotive industry. Not only do we see increasing usage of energy technology in more efficient batteries fueling automobiles from electric vehicles (EVs) to hybrid electric vehicles (HEVs), in tandem with vehicle electrification we see exponential integration of various communication technologies creating the connected car. This increase in complexity has posed new challenges for the automotive industry, which must juggle cost while keeping abreast of ever-increasing expectations for safety and convenience.
Telematics and staying connected
Let’s take a closer look at the convergence of automotive and communications technologies. In the 1970s, telephones were corded and came with rotary dials. If there was a family emergency and you were on the road, you probably would not be in a helpful position until you arrived home or at a known destination with a landline telephone. Today, you can respond to a quick message from a family member sent to your car asking you to pick up a carton of milk on the way home. Staying in communication has not only become de rigueur, but providing the technology to help people stay connected while on the road is nothing short of compulsory.
A technology of growing importance that has helped lead the connected car revolution is telematics. All over the world, the integrated use of telecommunications with information technology has grown so rapidly that various challenges have arisen, not only to set worldwide industry standards but also to ensure proper design and test solutions are available. This will provide sufficient safety net checks before drivers get behind the wheel.
Telematics applications include the use of wireless technology like 802.11p (also known as dedicated short-range communications (DSRC)) and cellular technologies, enabling V2V, V2I, V2N, and V2X communications between vehicles and infrastructure. An interesting area of discussion in the automotive industry regarding the future of the connected car is the growing role of cellular communications for V2V and V2X versus the ready and validated 802.11p DSRC solution that leverages unlicensed frequency spectrums. Two examples of Cellular V2X are LTE-V (3GPP Release 14) and 5G, the latter of which aims for 1 ms latency, 99.9 percent reliability, and 100x faster data rates than 4G and will bring benefits as well as design and test challenges to the automotive industry.
The European Commission announced a regulation requiring all new cars be equipped with an emergency call (eCall) module from April 2018 onward, so that in the event of a serious accident, the in-vehicle system (IVS) can report the emergency situation to a public safety answering point (PSAP) through the eCall platform. Other governments also have or will have similar regulations that save lives from car accidents. For example, Russia already operates its ERA-GLONASS platform.
On a more daily basis, though, telematics provide many conveniences for both drivers and passengers. For instance, a hungry driver could be informed when his or her favorite food and beverage chains are nearby – this development has opened up an entire new market segment for on-board advertisements, from cafes to clinics.
In other applications, some original equipment manufacturers (OEMs) already provide value-added, telematics-enabled services for their customers by having the vehicle automatically transmit diagnostic information about breakdowns or potential failures. These preventive maintenance notifications alert the driver to avoid the potential of a stalled vehicle on the road. Some high-end automotive OEMs also provide third-party-supported or private eCall services for emergency situations, with the ability to drill down to such details in addition to government-regulated or public eCall. For example, the European Commission’s mandated eCall communicates a minimum set of data (MSD) that includes vehicle type, vehicle identification number (VID), vehicle propulsion storage type (e.g., gasoline tank, diesel tank, compressed natural gas, etc.), time, location, direction, and so forth. Private eCall systems can provide additional detailed information such as road lane, mile/km marker, vehicle color, license plate, model, and the like. These are vital information packages that can increase the efficiency of rescue crews, and it is just a matter of time before mid-to-low-range vehicles adopt such telematics applications as the technology involved becomes more economical and consumer expectations rise.
Technology challenges and solutions
The rapid increase of telematics applications in all vehicles is already starting to pose design and test challenges. Among many design and test challenges connected car engineers are managing, three primary hurdles include interference, fading, and eCall verification.
As more wireless technologies are implemented in telematics units, a common issue will be coexistence and interference between telematics units. For example, 2G/3G/4G cellular, WLAN (a/b/g/n/p/ac/ax), Bluetooth, and GNSS technologyare all being integrated into a single transceiver module, which, as a result, has produced exponential increases in test complexity (Figure 1).
Another challenge connected car designers must to overcome is how to verify the performance of vehicular communications under fading conditions resulting from mobility. For example, the IEEE 802.11p standard specifies DSRC V2V radio channel models for fading conditions that simulate scenarios including rural line-of-sight (LOS), urban approaching LOS, street crossing non-line-of-sight (NLOS), highway LOS, and highway NLOS (Figure 2).
For eCall and ERA-GLONASS design and test, Keysight E6950A eCall conformance test solutions perform end-to-end functional and standard-compliant conformance testing of eCall modules, with optional audio performance analysis. The eCall software simulates a PSAP and controls a network emulator to emulate a cellular network and signal generator that provide GNSS coordinates required by the IVS to compile the MSD. This setup makes it possible to verify if the IVS modem is able to trigger an emergency call, send the correct raw MSD data, and establish a voice connection with the PSAP independently of any real-world mobile network.
The road ahead
As the auto industry continues to adopt a plethora of wireless technologies to help drivers connect with various information networks, automotive electronics OEMs and manufacturers need to continuously explore new test solutions that can provide comprehensive test coverage and ensure connectivity integrity. Ultimately, this will determine the quality and safety of each trip a driver (and vehicle) makes.
Keysight Technologies, Inc.
1. Keysight is working with LTE-V ecosystem players to solve LTE-V test challenges, and a member of the 5G Automotive Association (5GAA), collaborating with wireless communications and automotive leaders to set up 5G automotive test cases, define certification processes, address V2X test and interoperability challenges, and support trial deployments.