Discovering fine-grained RRC state dynamics and performance impacts in cellular networks

Abstract

To conserve power while ensuring good performance on resourceconstrained mobile devices, devices transition between different Radio Resource Control (RRC) states in response to network traffic and according to parameters specific to network operators. As RRC states significantly affect application power consumption and performance, it is important to understand how RRC state timers interact with network traffic patterns. In this paper, we show that the impact of RRC states on performance is significantly more complex and diverse than found in previous work. To do so, we introduce an open-source tool that allows the impact of RRC states on network and application performance to be measured in a robust and accurate manner on unmodified user devices, and deploy the tool in 23 countries around the world to test a broad range of cellular network technologies. We detect previously unknown performance problems which increase network latencies by up to several seconds and for LTE, can increase packet losses by an order of magnitude. Through an in-depth cross-layer analysis of several carriers, we examine the lower-layer causes of these problems. We determine that the highly complex state transitions of certain carriers, and in particular poor interactions between state demotions and network traffic, can lead to substantial, unexpected latencies.

Understanding RRC state dynamics through client measurements with mobilyzer

“…In addition to the novel results we have found (discussed in more depth in our full-length paper [12]) this approach allows us to continue to maintain a database of cellular network performance worldwide that reflects the evolving cellular network. We have also contributed to the Mobilyzer project [11] aimed at developing a large, comprehensive dataset of network measurements worldwide from the client perspective.…”

“…In the full version of this paper [12], we investigate fine-grained RRC dynamics and performance in more depth, including through other measurement approaches. Prior work has focused on measuring RRC state configurations in a controlled setting or on specific device types which make RRC transition event logs directly available to applications [8,10,9,13].…”

A First Look at Performance in Mobile Virtual Network Operators

“…We suspect that this is influenced by the RRC state machine at the radio layer as defined in the 3GPP standard [24], but we do not have visibility to actual RRC states using the commodity Nexus 4 phone to examine this further. Prior work (e.g., [19,34]) has also shown that inappropriately tuned RRC states impact web access performance. Overall, this suggests some potential misconfiguration or service differentiation at the radio layer for the MVNO B1 running over carrier B.…”

QoE Doctor

“…layer control plane messages used by the base station 1 to coordinate with the device. RRC state behavior has a significant impact on app performance and power consumption [22,33,40,41].…”