ECall design for automotive applications is still complex for many engineers, so today we'll talk about how enhanced eCall cars can be designed to be simpler, sharing some RF design expertise and integrated solutions to help meet some of the demanding product challenges in eCall applications.
What is eCall?
e-Call is a vehicle emergency call system in Europe that provides rapid assistance in traffic accidents. Its objectives are to ensure the safety of life, mitigate injuries and reduce property damage.
How it works: When an accident occurs, it automatically activates an emergency call or eCall through the vehicle's sensors. The system then automatically calls the European Emergency Services 112 call center. A telephone line will be connected to the emergency centre, sending details of the exact location of the accident via GPS. Next, the Emergency Dispatch Center provides appropriate assistance to the location.
Since 2018, all cars and vans sold in the EU must be fitted with an eCall system. The basic idea is to shorten emergency response time to reduce casualties and other accidents.
From a reliability point of view, the eCall system must be flexible, because when an accident occurs, the power cord of the battery may be cut off and the electronic equipment may be disconnected or damaged. Therefore, backup power sources such as small batteries are required so that the eCall system can operate effectively under harsh environmental conditions.
Traditional emergency calling methods
Some of the challenges faced by traditional design methods of traditional eCall systems:
1. Fr4-PC board materials require careful matching, which will increase insertion loss and reduce performance.
2. Additional matching and power supply circuitry will increase the heat dissipation temperature of the system, thereby limiting the overall performance of the system.
3. When the switching array is configured for different antenna configurations, design flexibility is limited.
4. Compared with non-dual SIM dual-pass (DSDA), DSDA has limited ability to implement a common layout of higher-end design models.
Solutions address challenges through integration
Complexity can be easily addressed by implementing simple integration on some RF paths. While this approach significantly reduces some complexity, path loss, and matching challenges, it won't help much with your design improvements. As shown in Figure 1, integrating some switches does help reduce matching, eliminating the need for many GPIO controls, replacing them with fewer MIPI (MIPI — Mobile Industry Processor Interface) controls, and reducing the number of switches. This approach can also save costs, although the cost savings achieved are very small compared to a fully integrated approach.
Figure 1: Example of an eCall switch architecture with some level of integration
As shown in Figures 2 and 3, a fully integrated approach allows for more improvements that the integration shown in Figure 2 cannot achieve. Figure 2 uses a DSDA switch option architecture that reduces front-end matching and RF losses, uses an RFFE MIPI control, integrates all dividers in one package, and reduces material cost and design time.
Figure 2: Example of a Fully Integrated eCall Switch Architecture— Using a Pin-Compatible Optional DSDA (QPC1252Q)
Figure 3 shows a design similar to Figure 2, but without integrating the DSDA switch option architecture. However, it still requires a small amount of RF front-end matching to provide all the benefits shown in Figure 2.
Figure 3: Example of a fully integrated eCall switch architecture—using a non-DSDA (QPC1251Q) routing switch
Qorvo expands its portfolio of automotive eCall solutions to improve emergency communications
Qorvo's high-performance broadband antenna switches for emergency calling (eCall) help ensure connectivity to lifesaving services after an accident. With these switches, the vehicle's main cellular signal can be automatically relayed (or hot-switched) to an undamaged car antenna for help.
The Qorvo Automotive Family adds the QPC1220Q high linearity wideband dual-pole four-throw (DP4T) antenna routing switch, which has a fully operational range that meets the requirements of AEC-Q100 Class 2 automotive certification. With up to +34 dBm hot switching capability, it is ideal for all remote communication control unit (TCU) eCall and antenna routing configurations. In addition, it reduces insertion loss by up to 1 dB, maximizing the effective power delivered to external eCall antenna arrays, enabling better cellular and 5G connectivity even in areas where signal coverage is limited.