Author: Jens Berger

Jens Berger is full-time Head of Applied Research and part-time Technology Marketing Manager. With a Ph.D. in Electrical Engineering and fascinated by signal analysis and objective quality models in audio and video services, he's responsible for defining the test scenarios in our products. Jens holds several patents for testing and measurement procedures and supports our international standardization efforts, leading a working group in the ITU-T Study Group 12 concerned with global QoS/QoE standards. In his posts, he enthuses over reproducing human perception in telecommunication services and analyzing their technical background.

What is the market for voice telephony in 2017?

voice telephony

In competition with messaging services and Facebook and Instagram timelines, is voice telephony at all relevant in 2017 and beyond? We believe: yes, absolutely! Telephony is still the most direct and most efficient way of telecommunication. Apart from being an auditory interaction, voice still transports much more emotion – and opportunity for clarification – than any emoticon ever could. Or,…


Proofing and optimizing a network’s readiness for video transmission

video quality measure

In previous entries of this blog series about the challenges of mobile video services, we discussed video quality as a perceived metric, how it can be measured, and how quality measuring algorithms work. To conclude the series, this post focuses on how to apply a video quality measure to quantify video services as consumed by subscribers. What are the challenges…


What different models for predicting visual quality exist? What models are applicable for which test cases?

visual quality

In a previous blog entry about the challenges of mobile video services, we discussed video quality as a perceived metric and how it can be measured subjectively in viewing sessions. In this post, we will take a closer look at automated video quality measurement methods, often called objective measurements, which are applied in real field video quality measurements. An objective…


Evaluating visual quality and video MOS based on subjective perception

Visual quality

Video services are very popular and so is their use today in various services and media. YouTube and Netflix are merely the pioneers in video streaming; many other services have followed. Broadcasting stations move more and more content online, videos are shared via social media, and peer-to-peer applications are on the rise; for example, video chat services (e.g. Skype), or…


VoLTE is real, VoLTE is now – the latest measurement results

In early 2015, the first operators enabled Voice over LTE (VoLTE) for their customers in Europe. This requires LTE coverage, a VoLTE-capable phone and – at least in the first months – a dedicated subscription. Today, LTE coverage is widely available and state-of-the-art devices support VoLTE natively. Now is the time to answer some questions: Does VoLTE improve telephony for…


Challenges of mobile video services for network operators

mobile video services

Mobile video services by far demand the biggest chunk of data in today’s mobile networks. According to the Cisco Visual Networking Index (VNI) Forecast 2016, by 2020, video services will account for 75% of all data consumption. The performance of video services has a large influence on customer satisfaction. For the mobile network operator, the decision to deliver higher or…