Energy Efficient Network Deployment With Cell DTX

Cell discontinuous transmission (DTX) is a new feature that enables sleep mode operations at base station (BS) side during the transmission time intervals when there is no traffic. In this letter, we analyze the maximum achievable energy saving of the cell DTX. We incorporate the cell DTX with a clean-slate network deployment and obtain optimal BS density for lowest energy consumption satisfying a certain quality of service requirement considering daily traffic variation. The numerical result indicates that the fast traffic adaptation capability of cell DTX favors dense network deployment with lightly loaded cells, which brings about considerable improvement in energy saving.

I. Introduction

MOBILE operators are facing an exponential traffic growth due to the proliferation of portable devices that require a high-capacity connectivity. This, in turn, leads to a tremendous increase in energy consumption of wireless access networks [1]. A multitude of studies have been recently proposed to increase the energy efficiency of these networks. Among them, cell discontinuous transmission (DTX) is a new hardware feature enabling the deactivation of some components of a base station (BS) during the empty transmission time intervals (TTIs). With the introduction of cell DTX, a cell can be put into sleep mode when there is no traffic, which significantly lowers the idle power consumption. Unlike long term sleep schemes [1] that aim to switch off the cells completely during low traffic periods, cell DTX leaves certain parts of the cells active to ensure that the cells will be immediately activated upon request. This enables node-level power consumption adaptation in accordance with traffic variation in a very short time scale (millisecond level) without necessitating any network level cooperation schemes.