The mobile video traffic volumes are growing at a tremendous rate [1]. On-demand video streaming to smartphones is already considered as business as usual. The next step in this evolution is widespread use of real-time and interactive video, such as live streaming and video calls. Many such Over The Top (OTT) services already exist, such as Skype, FaceTime, Google+ Hangouts, and Tango.

One of the major problems with the real-time OTT video streaming services is their large energy consumption where the wireless communication part is one of the largest contributors. While on-demand video streaming services can deliver video content in large bursts in order to optimize the energy consumption [2], such strategy is impossible with real-time video because of the timing constraints. Note that the radio network is completely oblivious towards these OTT services providing the same treatment as for any other data traffic.

Voice over LTE (VoLTE) [3] is currently getting deployed in the LTE networks around the world. Currently, most LTE networks still use circuit switched fall back (CSFB) to serve voice calls but VoLTE is going to change that. Concerning energy efficiency, the key feature in VoLTE is the use of optimized DRX profile. That mechanism enables, at least in theory, the smartphone’s LTE radio to sleep most of the time and to only wake up for a very short time to receive a single voice packet every 20ms or 40ms. In principle, the same VoLTE mechanisms could be leveraged with real-time video. The challenge in terms of energy efficiency is the larger volumes of data generated by a video stream compared to a voice stream.

Objectives and description of work

The first stage in this thesis is to investigate the energy efficiency of mobile OTT real-time video streaming/video call applications when used over LTE. In the next phase, the student should quantify the energy savings achievable through the use of VoLTE mechanisms together with optimized DRX profiles to serve real-time mobile video compared to the OTT services. In this phase, it is necessary to consider different video codecs and investigate the tradeoff between energy consumption and video quality.

References

[1] Cisco, “Cisco visual networking index: Forecast and methodology, 2012-2017,” Cisco, White Paper, May 2013.

[2] M. A. Hoque, M. Siekkinen, J. K. Nurminen, and M. Aalto, “Dissecting mobile video services: An energy consumption perspective,” in Proceedings of the 14th IEEE International Symposium on a World of Wireless, Mobile and Multimedia Networks (WoWMoM), Jun. 2013.

[3] NSN, From Voice over IP to Voice over LTE, While Paper, 2013:http://nsn.com/system/files/document/nokia_siemens_networks_smarts_lab_volte_white_paper_05072013_online.pdf