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Why a software-only radio in times of digitalization?

Why a software-only radio in times of digitalization?

Today, radios in cars are generally taken for granted. Despite the numerous communication channels that are available to every car driver, conventional radios (such as AM/FM) are still desired by most vehicle customers: every new car comes with an in-built radio.

On the other hand, the automotive infotainment systems are changing: new features, more connectivity, integration with non-automotive devices and higher user expectations are drastically changing the classical infotainment landscape in the dashboard.

Retrospective ​

In the beginning, car radios were “simple” receivers of analogue broadcast audio (AM/FM).

Radios evolved to offer more services (e.g. traffic, metadata, etc.) and become part of In-Vehicle Infotainment (IVI) systems to meet the growing expectations of users for rich information and entertainment. Radios grew in complexity e.g. supporting multiple analogue and digital broadcast standards and technologies, within an increasingly complex IVI system (e.g. richer multimedia, better navigation and increased connectivity).

The evolution of car radio systems can be categorized in generations:

The 1st generation (past) car radio system supported a wide range of standard-specific Radio Frequency (RF) hardware receivers. For every region and standard there was a specific RF receiver.

The 2nd generation (present) car radio system incrementally improved the design of the 1st generation to manage multi-standard and wideband RF receivers, which are now able to handle several broadcast standards. This allows hardware to be reduced.

The 3rd generation (future) car radio system will reduce the hardware further by replacing the RF standard-specific decoders (today often part of the RF chip) by so called Software Defined Radio (SDR) libraries. Hardware will be replaced by software.

In-Vehicle Infotainment Systems

Until mid-2010 almost all OEMs were endeavouring to develop  complex IVIs individually. It turned out, however, that these individual solutions were too costly. So they gathered with Tier 1 suppliers in consortia, creating standardized IVI system components (e.g., GenIVI, Automotive Grade Linux). In the meantime, Google pushed its operating system Android into the automotive domain, leveraging its strengths and appeal from the Consumer Electronic (CE) appliances, such as smartphones and tablet. Within years, Android grew to become a de facto accepted standard for the IVIs.

The automotive industry and manufacturers of car radios continued investing big effort in proprietary IVI systems to provide an alternative solution, but their IVIs lacked the feature of the CE counterpart: for example, they allowed limited (or none) information exchange with the smartphone, i.e. the data repository of today’s connected user. Furthermore, these systems could not cope with the rapid cycles that are typical of the CE domain (for the smartphone roughly two years). The customer expectations of the infotainment in the car kept growing and most of the car makers accepted Android as standard. Only a few, mainly premium, OEMs still strive to provide proprietary systems to their customers. The adoption of Android, in turn, encouraged Google to increase even more of its efforts in the automotive industry. Despite the initial difficulties, Android OS improved and is rapidly closing the gap to its CE counterparts. With every new generation, Android OS becomes the feature-rich infotainment system that consumers expect.


Android (and the apps on top of it) offers many features, but not the radio. The Google app store offers dozens (maybe hundreds) of radio apps and gives the impression that Android comes with radio features that can be easily installed and removed, just like a navigation or a media player app.

Instead, users can install either an IP radio (Internet Protocol Radio, i.e. no FM, no digital radio) or a “skin” that steers the underlying radio tuner preinstalled by the smartphone manufacturer. Android does not come with an analogue or digital radio tuner solution. It is the smartphone manufacturer that implements the radio tuner based on the specific radio chip used. The radio lays “beside” Android.

The reason why “old school” analogue and digital (e.g. DAB) technologies are still needed is internet availability: the driver expects that the radio services are always available, at a constant (good) quality in almost every location and at every speed. Today, only analogue and digital broadcast radio (e.g. DAB) can fulfil these expectations. IP radio can’t, as internet coverage is not ubiquitous and even where it is present, limited bandwidth might turn listening into an unpleasant experience.

IP radio might replace the traditional ones one day, but not yet: the classic broadcast technologies will still remain an integral part of the IVI system for some time. Until then, hybrid radio solutions (like hybrid IP) will be used to complement the analogue and digital standards with additional services provided by IP.


OEMS and Tier 1 suppliers have several challenges concerning radio in the car:

  • They need to address worldwide markets with different broadcasting standards, such as analogue (AM/FM) and digital (DAB, Digital Audio Broadcasting in Europe; HD-Radio, High Definition Radio in the US; CDR, Convergent Digital Radio expected to be released in China soon)
  • They need to reduce their supplier base, not having a different radio supplier for every car line and every geographical market
  • They want to reduce the cost of hardware: new radio concepts allow for the sharing of tuners among different broadcasting technologies (e.g. DAB and FM), eliminating the need for separate tuner hardware for each RF band. Furthermore Software Defined Radio (SDR) – i.e. the possibility to use software instead of hardware for complex decoding – allows the consolidation of radio functionality on top of powerful domain controllers, eliminating even more of the radio specific hardware.
  • They request shorter development time and time to market by shorter development cycles (e.g. quick prototyping). Furthermore, they want to reduce the burdensome qualification/system tests/field tests, which comes with every supplier change and with every new ECU (Electronic Control Unit, i.e. the hardware)
  • They want to have a flexible architecture to easily “move” functionalities on top of the most appropriate ECU (e.g. move on top of a remote controller near the antenna to avoid long cables) or implement new secure concepts (e.g. shut down at run-time functionalities under threat, while a redundant functionality starts on a different ECU)
  • They want to avoid hardware lock-ins and wish to be able to change suppliers.
  • They want to avoid costly recalls by enabling Over The Air (OTA) update.


OEMs and Tier 1 suppliers don’t want to have just an Android-compatible radio solution. They want to have a radio solution that works just like Android: scalable, hardware-independent and remotely updateable. They want a radio platform in software form , that they can configure to suit many variations and eventually “move” from one hardware to another one.

Challenges Of A Complex IVI System

There are numerous challenges to develop a software-based radio platform as the complexity has dramatically increased in recent years. The radio logic in car radios, for example, has become highly intelligent software, which needs to control a multitude of reception paths, running in the foreground and background, in order to provide the user with an exact image of the broadcast services available at all times. The services that can be received are supplemented by the corresponding metadata from different sources.

Also, the RF broadcast receivers, have become more complex as they are now multi receiver and multi band systems, supporting different reception standards, simultaneously assembled in one package.

This results in a very complex system architecture sharing important hardware resources among each other dynamically.

A strategy to theme this complexity is to introduce standards.

The rise of a standard such as Android helps to reduce the system complexity and eases the IVI system integration by providing stable interfaces. Android is doing well in the process of standardizing its lower interfaces (towards the hardware) and its upper interfaces (towards the apps and HMI). Apps are a way to cope with the complexity of the car infotainment. The components are developed on a standard, reference platform and can therefore be easily integrated into platform-compatible products, i.e. on platforms which comply with the interfaces. Potentially the same apps can be used on smartphones as well as in the car and across different Android generations. Developers can increase the distribution base of their application to every device that complies to the standard. This creates a win-win situation for everyone in particular for the customer, who now has access to multiple constantly updated functions/apps.

What is true for the standardization of the Operating System (OS), is true also for the function: standardizing features such as navigation or speech recognition reduces effort in handling complex IVI systems. The same applies for radio: a standard radio solution able to provide radio functionalities for all relevant broadcast standards greatly supports the integration efforts.

OpenSynergy’s Radio Tuner SDK

OpenSynergy’s Radio Tuner SDK is a software radio product that is a pre-tested, mass-production proven software component with more than 10 years’ history. It fulfils all the requirements described above (e.g. Android compatibility, support of all relevant broadcasting standards, hybrid radio, support for shared tuner management, etc.). The development is based on a Linux or Android reference platform using ARM based SoCs (System on Chip) and it is easily portable to comparable platforms. Its hardware abstraction layer supports the commonly used automotive RF receivers and decoders. The architecture is also designed to support the future SDR modules, planned to replace the current hardware solutions.


The Radio Tuner Stack is a standardized component. Its interfaces to the operating system (most important of all: Android Automotive) have been standardized and it therefore substantially reduces  the effort to integrate the component when starting a new project.  Moreover, it minimizes the time for retesting and requalification (delta testing instead of a “full-fledged” testing).

The Radio Tuner Stack can be applied for flexible E/E architectures (Electrical/Electronic architecture), such as “remote tuner” concepts, in which the radio stack is located on the most suitable vehicle ECU. This could be useful, for example, when trying to reduce the impact of local interferers (a case particularly important in electric vehicles, where the radio needs to be placed far away from high current elements) or to reduce the wiring from the antenna (e.g. directly in the roof antenna).

It is also prepared to support highly complex broadcast receiver SoCs: an intelligent shared tuner management layer separates the management of the dynamically shared resources from other tasks, to provide always the best compromise between available system resources and required functionality.

The Radio Tuner SDK is not only a software stack, but a complete development environment that supports the integration, testing and release of the product. It comes with:

  • an example application that allows the verification of all interface functions on the target hardware, even if the final human machine interface (HMI) is not available.
  • a service tool/quality monitor tool that gives insight into the internal processes of the tuner software during the development phase. During verification and test drives it allows the visualization of the behaviour under real circumstances.


The car radio has technically come a long way from the audio-only to single-RF tuner support solution it once was.

At the same time, the automotive E/E architecture requirements have increased, pressing OEMs and Tier 1 suppliers to find new, more flexible solutions (e.g. remote tuners) and solutions that work with the emerging IVI Android defined standard interfaces.

Radio Tuner SDK is OpenSynergy’s response to these emerging challenges. It offers a software product that meets the growing requirements of automotive customers in terms of functionality, costs, development time and quality. The Radio Tuner SDK is a mass-production proven product, which supports the worldwide most common analogue and digital standards. It supports all standard interfaces defined by Android and it supports the most used automotive RF receivers and decoders, thanks to its hardware abstraction layer.

OpenSynergy radio stack supports the “2nd generation tuner system” on the brink of becoming a “3rd generation tuner system”, as defined above in the paper, and is continuously enhanced to make full usage of the receiver trends and technologies of the next generation, i.e. Software Defined Radio