Improving LTE/LTE-A UE Power Efficiency with Extended DRX Cycle

Recently introduced UE types, such as Machine Type Communications (MTC) devices, require extremely efficient power saving mechanisms to operate in harsh situations for a long period with limited charging opportunities. Typical MTC devices, e.g., meters or sensors, access the network very infrequently, once per a few days or even months, but they have to suppress their power consumption as much as possible to survive the period with batteries or internal power sources with limited generation capabilities. During the idle mode in which the activity of UE is minimal, UE has to periodically monitor a control channel, PDCCH, to receive paging messages or identify whether system information is updated. In the LTE/LTE-A nomenclature, such a period is called Discontinuous Reception (DRX) cycle. In this paper, we outline the envisioned gain in power consumption when longer DRX cycle is applied, and explain the procedures to enable longer DRX. We analyze the impact of introducing the feature on the operation of the networks, and provide a guideline to facilitate longer DRX.