the typical LTE smartphone user consumes more than 1 GB data per month and most of the traffic is in downlink direction. One exception is mass events that typically turn to be uplink limited. The traffic-related signalling traffic is high up to 500 packet calls per subscriber per day or one packet call every 2 minutes during the busy hour. That leads to 10% of LTE subscribers being RRC connected simultaneously. Different OSs and applications such as Instant Messaging or music streaming have different impact on smartphone's performance and cellular network depending on specific implemen- tation decisions. In general, longer keep-alive periods and data compression are important factors which help applications to behave more friendly and improve user's perception. Battery life for smartphones is one of the optimization areas. The battery life depends on how services and applications are implemented, but there are also functionalities in the cellular network such as cDRX which when optimized can significantly improve current consumption. Other functionalities, such as Carrier Aggregation, can improve battery consumption for large data transfers, but affect negatively with short data transfers. VoLTE and OTT VoIP solutions are very important since the traditional circuit switched voice service is not available in LTE networks. While various VoIP solutions can provide very good voice quality and user experience in certain conditions, it takes a fully integrated VoLTE solution to achieve high standards of voice quality consistently, maintain similar battery life as legacy circuit switched voice, maximize network voice capacity and ensure seamless mobility towards legacy systems. The power consumption of the cellular subsystem in the smartphones has improved con- siderably during the last few years with the new RF optimization solutions. The small cell solutions can also reduce the smartphone power consumption by using lower UE transmit power levels. References [1] 'Smartphone Traffic Analysis and Solutions', Nokia white