Study of Signaling Overhead Caused by Keep-Alive Messages in LTE Network

Keep-alive messages generated from always-on type applications on smartphones can lead to frequent transitions between Long Term Evolution (LTE) Radio Resource Control (RRC) states, pushing significant increase of signaling traffic. In this paper, we investigate the performance of signaling overhead caused by keep-alive messages based on LTE RRC state transition procedure for various RRC inactivity timer settings. We propose a series of metrics for evaluating the signaling load in terms of system resource consumption on data and control channels for both uplink and downlink. The results show that although the RRC signaling overhead make keep-alive messages transmission with low efficiency, it will not consume the system resource dramatically and overload LTE network. The results also show that proper inactivity timer setting will reduce the signaling overhead and improve the efficiency of keep-alive messages transmission.