An Adaptive Energy Saving Mechanism in LTE-Advanced Relay Systems

The issue of energy saving (ES) has long been much concerned due to the ever increasing demand for services in advanced networks. To meet the requirements of spectral and energy efficiency improvement, the concept of heterogeneous networks (HetNet) is proposed in long term evolution-advanced (LTE-A) framework. In this work, we study one promising kind of HetNet nodes, the LTE-A relay node (RN), and propose an adaptive energy saving mechanism dedicated for LTE-A relay systems. Generally, since no direct link or interface is available during the dormant period, sleep relays need to receive the reactivation request from the donor enhanced Node B (DeNB) in a constant time interval. In order to save the overall power, the sleep interval of relays can be adjusted adaptively in the proposed mechanism, based on the demand of multi-service and cell load. Then a novel method of parameter mapping between tuning parameters for sleep interval and QoS parameters is introduced. We also discuss the system requirements for implementing the mechanism. Simulation results validate the advantage of our scheme, for the frequency of wake-up listening by RNs is reduced significantly in contrast with conventional fixed sleep interval mechanism.