We are all watching a lot of video on our mobile devices. In 2017, for the first time ever, mobile devices overtook desktop computers in video consumption, as the rollout of 4G and increasing data bundles has driven mobile use. This puts mobile networks in a challenging leadership position.

More than 50% of mobile traffic today is already video and it’s going to keep growing. By 2022 video will account for 75% of mobile traffic, which translates to approximately 71 exabytes (71 billion gigabytes) of data – an eight-fold increase from 2016 [1].

 

 

As mobile networks evolve to become video networks, mobile operators are faced with a daunting task: how to ensure a good quality of experience (QoE).

Furthermore, users are very sensitive when it comes to video streaming. We are easily annoyed by streaming delays to the point of abandoning the service: an estimated four out of 10 of us quit videos the first time they start re-buffering [2].

Vodafone is testing Multi-access Edge Computing (MEC), alongside other technologies, to improve the experience our customers get when watching videos on their smartphones and tablets.

MEC offers cloud-computing capabilities and an IT environment for processing applications and services – like video delivery – at the edge of the network, close to end users and connected devices. The MEC environment is thus able to provide ultra-low latency with virtually no jitter, which enables smooth broadband video streaming. It is also important to note that MEC is an open industry standard defined by the European Telecommunications Standards Institute (ETSI) and backed by industry leaders.

Vodafone Group’s Research & Development department, with partners Saguna Networks and Teragence, set out to measure and quantify the benefits of Multi-access Edge Computing on the QoE for HD video streaming.

We set up a Saguna vEdge MEC platform in our comprehensive 4G LTE lab and deployed two identical video streaming servers – one in the public cloud and one on the MEC platform. We simulated different values of radio access congestion and latency to examine the benefits of edge-hosting versus hosting outside the mobile network in terms of video QoE improvements. Teragence’s crowdsourced measurements helped us to validate our lab simulations, providing detailed information on real-world latency and congestion conditions.

We focused on three important video QoE KPIs and observed the following:

  • time to start: the time interval between clicking play and when the video starts. We found that longer latency had an almost linear correlation with the time taken for the video stream to start playing;
  • number of stalls (re-buffering events): a numerical count of how many times the video pauses for re-buffering. We observed no stalls in the case of MEC-hosted video streaming, whereas multiple re-buffering events were observed in the case of cloud-hosted video streaming, with the number of re-buffering events growing as latency increases; and
  • waiting time: the total time spent waiting, which is calculated by adding together all the re-buffering pauses. Waiting time grows exponentially as latency increases, suffering from the compounded effect of latency and congestion. Hosting video streaming on MEC servers in the Radio Access Network (RAN) eliminated this waiting time.

According to our findings, 1 in 5 users of 4G is likely to get a non-optimal video streaming experience when consuming content from streaming servers in typical hosting locations outside the mobile network. This research provides concrete evidence for the benefits of MEC-based video streaming.

Our work on this topic won the Biggest Contribution to R&D award at the MEC Congress in Berlin in September 2017, in recognition of a successful partnership making progress on a highly-debated topic. Next steps include research into benefits achievable for higher-resolution content, cost efficient use of this technology, comparison of tradeoffs in user experience when other solutions for streaming from the cloud are used, and business models.

By using this technology, mobile operators’ 4G networks can be transformed into better performing video delivery networks [3], while simultaneously preparing the network to support the needs of 5G low-latency applications.

Mobile video streaming is only one of many potential edge computing applications. We hope to see additional initiatives that assess the performance benefits of MEC for a wide range of other applications: from Internet of Things to Virtual Reality /Augmented Reality, connected cars, and more.

 

Dr. Simone Mangiante is a research and standards specialist in Vodafone Group. His main research interests are computer networks, SDN, cloud and Multi-access Edge Computing. He holds a PhD in Computer Engineering from the University of Genoa.

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[1] https://www.ericsson.com/assets/local/mobility-report/documents/2017/ericsson-mobility-report-june-2017.pdf

[2] https://mux.com/blog/buffering-reduces-video-watch-time-by-40-according-to-research/

[3] http://mobileworldlive.com/wp-content/uploads/2017/02/19345%20Mobile%20Video%20Survey%20Report.pdf