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EVS - the CODEC for better acoustic quality in all networks

Since the introduction of 4G LTE and VoLTE in 2016, voice quality in mobile networks and in smartphones has been evolving rapidly. With the EVS (Enhanced Voice Services) codec, we have a technology at hand that not only transmits voice data crystal clear, but also keeps the required network bandwidth for phone calls as low as possible.

Two trends are speeding up the use of technology for HD Voice quality:
First, the shutdown of 3G networks is accelerating the replacement of end-user devices, as many smartphones that previously only supported 3G now have to be replaced with new 4G or 5G devices with HD Voice capabilities.
On the other hand, an accelerated replacement of phone equipment is also taking place in the fixed network as a result of the almost completed migration to All-IP connections. Here, too, modern corded or DECT phones that support HD Voice with the G.722 codec will be used.  

Voice quality

With the use of the EVS codec in the networks of the network operators and the end devices of the users, the voice quality in the fixed network and mobile communications is then absolutely comparable with the quality of OTT telephony via the common messenger apps. 
Network services such as voicemail or IVR solutions also benefit from HD voice quality and the EVS codec through improved user experience. Many users with current smartphones or landline devices have already become used to the high voice quality and take it for granted.

Which technical innovation does the EVS codec offer?

In terms of voice quality, the EVS codec is the first implementation to process audio frequencies up to 20 kHz in fullband mode. As a reminder, the entire human audible spectrum ranges from approximately 20 Hz to 20 kHz, but decreases with age.

In addition to adapting the audio bandwidth, the EVS codec, by means of speech compression, also enables a significant reduction of the data to be transmitted in the networks. Depending on the available bandwidth in the respective IP networks, the codec adapts the compression rate and adjusts the required transmission bandwidth within a very wide range from 5.9 Kbit/s to 128 Kbit/s.

The evolution

Since the introduction of ISDN in the 80s of the last century, the codec G.711 with an audio bandwidth of up to 3.4 kHz (=narrowband) was the reference. The AMR-WB (Wideband) codec, already used in the 3G UMTS networks, was the following milestone, doubled the audio bandwidth to 7 kHz and offered significantly improved speech intelligibility. The EVS codec now increases the audio bandwidth to 20 kHz and presents significantly more details during phone calls in Hi-Fi quality.

Benefits of the EVS technology for network operators

All solutions based on the CreaLog platform SDP7 fully support the EVS codec and many other codecs.
With the help of Full-HD Voice technologies, service providers overcome the previous limitations in their networks, such as reduced audio bandwidth and codec-only focus on speech intelligibility. Via QoS management in 4G/5G networks, EVS offers the possibility to outperform OTT messenger services (WhatsApp, Signal, Telegram, ...) not only in terms of audio quality, but also in terms of robustness and availability of services. This even gives network operators the opportunity to regain lost ground against OTT services.



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