Delay and Power Consumption in LTE/LTE-A DRX Mechanism with Mixed Short and Long Cycles

Energy consumption is a major concern in today's wireless communications due to the consensus for a greener world. LTE-Advanced (LTE-A) has been standardized for the fourth-generation mobile communications to meet the growing demands for high-speed wireless communications. However, high-speed signal processing on LTE/LTE-A user equipment (UE) causes excessive power consumption. The discontinuous reception (DRX) mechanism is a critical technique for tackling this issue. Delay constraint and power savings are two contradictory performance metrics associated with the DRX mechanism. Using recursive deduction and Markov model, this paper provides an in-depth analysis on the average delay and average power consumption of the DRX mechanism. Two performance metrics, namely, power-saving factor and relative power saving, are devised to assess the power-saving performance of the DRX mechanism. The accuracy of theoretical analysis is validated by computer simulations using the parameters in compliance with LTE specifications. The performance of the DRX mechanism is governed by a set of parameters that interact with one another in an intricate manner. Therefore, the values of key parameters are tested to assess their impacts on the performance of the DRX mechanism. The results shown in this paper give an insight into the operation and further improvement of the DRX mechanism.