Energy-Saving Technology in Indoor LTE System with DTX Based on CQI

Abstract

In LTE (Long Term Evolution) system, CQI (Channel Quality Indication) is a technical method to realize adaptive modulation and coding. The dispatcher of BS (base station) would allocate resource blocks to users dynamically based on CQI of uplink and downlink channels, which is necessary in the process of uplink and downlink transmission [1]. When the CQI level of the channel is high, the energy efficiency is high. On the contrary, when the CQI level of the channel is low, the energy efficiency is low. However, if signals are not transmitted until the quality of the channel is good, energy loss may be lowered in the expense of group delay. That is to say, we take CQI into account on the basis of the technology of DTX [2] [3] (Discontinuous Transmission). According to the result of simulation, the energy consumption can be reduced by using our proposed scheme. Particularly, the energy-saving effect is significant when the load is low.