Fraunhofer IIS and HARMAN Automotive are collaborating to enable reliable voice communication over satellite networks for connected vehicles. By integrating Fraunhofer’s AI-based NESC voice codec into HARMAN’s Ready Connect SatCom TCU, the companies aim to help automakers deliver bi-directional NTN voice services, including emergency calling beyond cellular coverage. The solution is designed to maintain high voice quality even under severe satellite bandwidth constraints, reducing required bitrates to 1 kbit/s or less while allowing OEMs to add satellite voice capability without redesigning the TCU. Learn more in this Q & A with Jan Nordmann, Division General Manager of Fraunhofer USA Digital Media Technologies.
What is the NESC codec, and why is codec selection especially important for voice communication over satellite links?
Mobile and satellite network operators, device manufacturers, and regulatory bodies are keen to make universal coverage a worldwide standard by efficiently integrating terrestrial and non-terrestrial networks (NTN). While current speech codecs work well for terrestrial 4G/5G voice services, they typically require 13 kbps or more of data transfer rate to achieve good audio quality – a fact which makes them unsuitable for large-scale applications of voice services over currently available narrowband (NB) NTN systems.
NESC is an ultra-efficient AI-based voice codec tailored for bandwidth-constrained networks that provides voice quality comparable to terrestrial phone calls while requiring 90%+ less data rate compared to conventional voice codecs. Its ability to transmit intelligible and natural sounding voice at bitrates of 1 kbps or less makes it possible to deliver NTN voice services over current NB-IoT GEO while also enabling at scale deployment of high-quality voice over future NR-NTN LEO constellations.
NTN voice will reach the market as consumer-facing services on phones, in cars and aircrafts as well as in professional applications such as maritime environments, farming or defense. This will include a facet of voice applications including full duplex bi-directional voice, voice messaging or push-to-talk. Offering voice services over satellite will not only be about ‘extending the service coverage and convenience’ but will serve as a complement to existing text-based messaging and potentially save lives in emergency situations.
How did the collaboration between HARMAN and Fraunhofer enable the Ready Connect Automotive Satcom voice demo?
The HARMAN Ready Connect telematics control unit solution adds NB-NTN satellite connectivity to the terrestrial options and therefore allows vehicles to always be connected no matter where. Fraunhofer’s resource efficient NESC encoder and decoder software has been implemented as a proof of concept (POC) on the Ready Connect TCU in real-time with minimal integration effort. For the POC, a second voice client with NESC encoding/decoding was implemented on a companion laptop which acted as the ‘emergency service center’ and enabled the visitors to experience an emulated bi-directional voice call.
What capabilities of the Fraunhofer codec make it suitable for bandwidth-constrained satellite voice applications?
The innovative AI-based approach of NESC to voice pre-processing and encoding/decoding was a necessity to achieve the level of coding efficiency of 1 kbps or less required for reliable satellite voice applications while keeping compute and memory consumption in a range that allows for the implementation on current generation SoCs. NESC’s language agnostic algorithm allows for global deployment of NB-NTN voice services with a high level of intelligibility.
What are the broader implications of HARMAN and Fraunhofer’s collaboration for the automotive industry as vehicles expand beyond terrestrial connectivity?
The automotive industry has relied on satellite connectivity for location-based services and in some markets, satellite radio services, for decades. But with the new generation of satellites in combination with spectrum availability, advancements in vehicle sound systems and software defined vehicles, many new opportunities and applications are emerging. That will in the immediate future enable satellite-based emergency services and voice messaging over NB-IoT GEO constellations. The next generation of NR-NTN LEO systems which will allow for a mass market deployment of satellite-based voice and even video services in cars are already in the making.
How should OEMs think about codec strategy as part of their broader connected vehicle and SDV strategy?
SDV (Software Defined Vehicle), by definition, allows OEMs to add features, functionalities and services after the point of sale. The ability of modern audio, voice and video codecs to run efficiently in real-time and entirely in software on automotive SoCs, nicely complements the SDV movement and will provide OEMs with the opportunity to update codecs, when more efficient or feature-enhanced versions become available. That, in turn, benefits consumers by providing access to continuously improved user experiences, which can then prolong the utility and freshness of a car.
The interview was first publish at the Harman blog.