Reference Signals for Improved Energy Efficiency in LTE

Cellular wireless systems have focused, to date, on system capacity, user data rates, latency and coverage as primary design criteria. Energy efficiency has recently received increased attention as another important criterion to be considered. The potential for energy savings in 3GPP LTE systems has been investigated in [1]-[3]. An important design element that determines the potential for energy efficient transmission is the structure of reference signals that need to be transmitted independent of the load in the network, such as the cell-specific reference signals (CRS) in 3GPP LTE systems. This paper discusses modifications to the reference signal structure in LTE that can enable greater energy efficiency. The time and frequency estimation performance implications of such modifications are evaluated and discussed.