DRX mechanism for power saving in LTE

Enhanced discontinuous reception mode is supported in long term evolution of 3GPP standards to conserve the mobile terminal's battery power. Furthermore, there are additional advantages in using DRX, such as over-the-air resource saving on both the uplink and downlink to increase overall system capacity. One of the enhancements over 3G wireless systems is that in LTE DRX mode can be enabled even when the user equipment is registered with the evolved node-B. However, there is a need to optimize the DRX parameters, so as to maximize power saving without incurring network re-entry and packet delay. In particular, care should be exercised for real-time services. In this article the power saving methods in both network attached and network idle modes as outlined in LTE are explained. The optimum criteria to select the DRX mode are defined for different applications. Analytical/simulation results are presented to show the power saving/connection reestablishment and packet delay.