Optimized Energy Management for Mixed Uplink Traffic in LTE UE

Abstract

Battery life is a major issue for any mobile equipment, and reducing energy consumption via energy management in 3G LTE user equipment (UE) will be essential for the delivery of a variety of services. Discontinuous transmission (DTX) and reception (DRX) have been designed to facilitate power management, but they can provide energy savings only via proper tuning. Relevant work in the literature mainly pertains only to discontinuous reception mode (DRX) for downlink data. However, today's increasingly powerful UEs can generate and upload significant amount of data. This paper proposes an energy management framework applicable to both discontinuous transmission (DTX) and DRX power saving modes. In particular, in DTX mode it can reduce UE energy consumption for uplink intensive applications like telemedicine or social networking. The proposed novel energy management framework is based on jointly using a-priori analytical evaluation of a M/G/1/K finite uplink queue system for mixed traffic with an optimized DTX/DRX algorithm. DTX mode is modeled by an expression, through which the impact of quality of service (QoS) parameters on the UE's mean energy consumption for uplink transfer is determined. The model extracts and operates on the values computed for the M/G/1/K queue. Finally, a dynamic energy management algorithm for DRX/DTX modes is proposed for energy consumption optimization based on an integrated Analytical Hierarchy Process (AHP) and Grey Relational Analysis (GRA). Analytical evaluation has shown that using our algorithm to tune DTX can achieve 49-73% energy saving over not using DTX.