The popularity of smartphones and mobile applications has experienced a considerable growth during the recent years, and this growth is expected to continue in the future. Since smartphones have only very limited energy resources, battery efficiency is one of the determining factors for a good user experience. Therefore, some smartphones tear down connections to the mobile network soon after a completed data transmission to reduce the power consumption of their transmission unit. However, frequent connection reestablishments caused by apps which send or receive small amounts of data often lead to a heavy signalling load within the mobile network. One of the major contributions of this paper is the investigation of the resulting tradeoff between energy consumption at the smartphone and the generated signalling traffic in the mobile network. We explain that this tradeoff can be controlled by the connection release timeout and study the impact of this parameter for a number of popular apps that cover a wide range of traffic characteristics in terms of bandwidth requirements and resulting signalling traffic. Finally, we study the impact of the timer settings on Quality of Experience (QoE) for web traffic. This is an important aspect since connection establishments not only lead to signalling traffic but also increase the load time of web pages. 1. Introduction Together with the wide-spread usage of smartphones in today's UMTS networks, the popularity of smartphone apps has seen a tremendous growth during the last years [1]. The resulting traffic is expected to exceed half of the global mobile data traffic in the next years [2]. One of the major reasons for this phenomenon is that smartphones are very convenient for users to stay always connected to the Internet. In turn, this has led developers of smartphone apps to the assumption of continuous Internet connectivity. Therefore, many apps such as social network clients, weather forecasts, or instant messengers update their status frequently, which raises a number of problems—in the mobile network as well as on the smartphones. In contrast to desktops or laptops, smartphones are equipped only with limited battery. Since established connections from the smartphone to the mobile network consume a large amount of energy, some smartphones close these connections soon after the data transmission is finished, that is, after a very short period of no traffic activity, which is controlled by an inactivity timer. This saves energy and prevents battery drain caused by established but unused connections. However, it
References
[1]
F. Cuadrado and J. Due？as, “Mobile application stores: success factors, existing approaches, and future developments,” IEEE Communications Magazine, vol. 50, no. 11, pp. 160–167, 2012.
[2]
Cisco, “Cisco visual networking index: global mobile data traffic forecast update, 2011–2016,” White Paper, 2012.
F. Qian, Z. Wang, A. Gerber, Z. Mao, S. Sen, and O. Spatscheck, “Profiling resource usage for mobile applications: a cross-layer approach,” in Proceedings of the 9th International Conference on Mobile Systems, Applications, and Services (MobiSys '11), pp. 321–334, July 2011.
[5]
F. Qian, Z. Wang, A. Gerber, Z. M. Mao, S. Sen, and O. Spatscheck, “Characterizing radio resource allocation for 3G networks,” in Proceedings of the 10th Internet Measurement Conference (IMC '10), pp. 137–150, Melbourne, Australia, November 2010.
[6]
Nokia Siemens Networks, “Understanding smartphone behavior in the network,” White Paper, 2011.
[7]
C. Yang, “Huawei communicate: weather the signalling storm,” White Paper, 2011.
[8]
S. Ickin, K. Wac, M. Fiedler, L. Janowski, J. Hong, and A. Dey, “Factors influencing quality of experience of commonly used mobile applications,” IEEE Communications, vol. 50, no. 4, pp. 48–56, 2012.
[9]
T. Ho？feld, D. Hausheer, F. Hecht et al., “An economic traffic management approach to enable the TripleWin for users, ISPs, and overlay providers,” in Towards the Future Internet—A European Research Perspective, G. Tselentis, J. Domingue, A. Galis, et al., Eds., pp. 24–34, IOS Press Books Online, May 2009.
[10]
D. D. Clark, J. Wroclawski, K. R. Sollins, and R. Braden, “Tussle in cyberspace: defining tomorrow's internet,” IEEE/ACM Transactions on Networking, vol. 13, no. 3, pp. 462–475, 2005.
[11]
Trilogy Project, “D2—lessons in “designing for tussle” from case studies,” Deliverable of the Trilogy Project ICT-216372, 2008.
[12]
S. Egger, P. Reichl, T. Ho？feld, and R. Schatz, “Time is bandwidth? Narrowing the gap between subjective time perception and quality of experience,” in Proceedings of the International Conference on Communications (ICC '12), p. 1325, Ottawa, Canada, June 2012.
[13]
P. H. J. Per？l？, A. Barbuzzi, G. Boggia, and K. Pentikousis, “Theory and practice of RRC state transitions in UMTS networks,” in Proceedings of the Global Communication Conference (GLOBECOM '09), pp. 1–6, Honolulu, Hawaii, USA, December 2009.
[14]
GSMAssociation and others, “Network efficiency task force fast dormancy best practices,” White Paper, May 2010.
[15]
F. Qian, Z. Wang, A. Gerber, Z. M. Mao, S. Sen, and O. Spatscheck, “TOP: tail optimization protocol for cellular radio resource allocation,” in Proceedings of the 18th IEEE International Conference on Network Protocols (ICNP '10), pp. 285–294, Kyoto, Japan, October 2010.
[16]
TR 22.801, “Study on non-MTC Mobile Data Applications impacts (Release 11),” 3GPP Std., 2011.
[17]
A. Díaz Zayas and P. Merino Gómez, “A testbed for energy profile characterization of IP services in smartphones over live networks,” Mobile Networks and Applications, vol. 15, no. 3, pp. 330–343, 2010.
[18]
C. Schwartz, T. Ho？feld, F. Lehrieder, and P. Tran-Gia, “Performance analysis of the trade-off between signalling load and power consumption for popular smartphone apps in 3G networks,” Tech. Rep. 485, University of Würzburg, January 2013.
[19]
M. Calder and M. K. Marina, “Batch scheduling of recurrent applications for energy savings on mobile phones,” in Proceedings of the 7th Annual IEEE Communications Society Conference on Sensor, Mesh and Ad Hoc Communications and Networks (SECON '10), pp. 1–3, Boston, Mass, USA, June 2010.
[20]
E. Vergara and S. Nadjm-Tehrani, ““Energy-aware cross-layer burst buffering for wireless communication,” in Proceedings of the Conference on Future Energy Systems: Where Energy, Computing and Communication Meet, p. 24, Madrid, Spain, May 2012.
[21]
S. Egger, T. Ho？feld, R. Schatz, and M. Fiedler, “Waiting times in quality of experience for web based services,” in Proceedings of the Workshop on Quality of Multimedia Experience (QoMEX '12), pp. 86–96, Yarra Valley, Australia, July 2012.
